Koyota,
I'd first just like to say, if you are understanding more than your able to say, then you are normal. Your ability to understand will always outpace your ability to produce. Just keep working. As one progresses, so does the other.
The keys to language acquisition are comprehensible input (CI) and repetition. Really, repetition is just a way to get CI, so CI is the biggest part. You should ask that your language partner speak in such a way that you understand 100% (minimum 90) of what she says. One of the easiest ways to get this is for her to be repetitive with what she says. Reusing vocabulary and grammatical elements until you understand them with no struggle. It's when this CI is getting in your head with no struggle that the real acquisition to fluency is happening.
Repetition sounds boring, but it doesn't have to be. You might check out TPRS online, particularly the parts on circling. Circling is a questioning style particular to the TPRS method that incorporates repetition in an interesting way. The most basic form starts with a basic sentence. A statement about something. Then it is followed by a series of questions that start by just checking comprehension. Then the questions can start eliciting new details. When new details are added they are incorporated into the original statement. When the sentence is full or the idea is complete, you move on to the next simple statement.
A concrete example:
The girl is riding her bike. (There are 3 parts to this sentence: the girl, is riding, her bike. So first your partner should circle each part.)
Is the girl riding her bike? Is the girl or the dog riding her bike? Is the dog riding her bike? Who is riding her bike?
Is the girl riding her bike? Is the girl riding her bike or eating her bike? Is the girl eating her bike? What is the girl doing with her bike?
Is the girl riding her bike? Is the girl riding her bike or her pogo stick? Is the girl riding her pogo stick? What is the girl riding?
(The basic pattern is yes/no with yes response, either/or, yes/no with no response, WWWWH question. Of course, this would be boring and too predictable so mixing it up is a good idea.)
(Then your partner can ask questions for new details.)
What's the girl's name? ... Susan is riding her bike.
How tall is the girl? ... Susan, the 6 foot girl, is riding her bike.
What color is her bike? .... Susan, the 6 foot girl, is riding her blue bike.
How big is the bike? ... Susan, the 6 foot girl, is riding her miniscule blue bike.
Where is she riding her bike? ... Susan, the 6 foot girl, is riding her miniscule blue bike down the street.
What time is it?... Susan, the 6 foot girl, is riding her miniscule blue bike down the street at midnight.
Why?... Susan, the 6 foot girl, is riding her miniscule blue bike down the street at midnight because she ...
The S in TPRS stands for storytelling. So the example above would likely progress into a story about Susan and why she is riding her bike and what she wants and her attempt to get it. The details and story are mainly to add interest. They just help keep student paying attention so they hear the repetitions of the main elements of the sentences. By the end of the first question cycle above, you will have heard the basic parts about 12 times each. If you can train your partner to repeat the sentence everytime you answer the question and use the negative of the incorrect response where applicable, you'll be hearing the basic parts closer to 50 times. (Here's how to get use the negative of the incorrect response: T-Is the girl riding her bike or eating her bike? S-Riding her bike. T-Good, she's riding her bike. She's not eating her bike. She is riding it.) Then when you add in the detail questions and the restating of the sentence with the new elements, you've got about 70 or 80 repetitions of the basic elements.
If you can train your partner in using repetition like this, you don't have to stick with make-believe stories. You can use current or historical events, TV shows, what happened during her or your day, etc. Anything that would be worth asking questions about and that can be simplified to a basic sentence (America elected a new president. I taught 10 classes today. Etc. From there the sentences can grow and details can be added. The country of America recently elected a new Democrat president who is very young and popular. I, the overworked English teacher, taught 10 mind-numbingly boring classes today on about 2 hours of sleep and with no advanced notice of the last 5 classes. Etc.). It's just that you want to hear all the grammar and vocab repeated lots and lots. So it won't sound like a normal conversation. It should sound like a conversation with someone who has severe short-term memory problems and needs any new information to be constantly incorporated with the old information. And if you think about it, lacking proficiency in a language is sort of like a severe short-term memory problem; you might be able to hear one word and then be able to look it up if needed, but as soon as those words come at you in sequence, the first ones fly out of your memory to make room for the next ones. By the end, you've forgotten all but the last word. So you need slow, clear repetition with new information added slowly.
I tried to get my tutor to do this with me, but it didn't work out. But since you have a language partner who asks you to create the lesson, then perhaps she will be more open to trying this. It does take training though. And to make it more interesting, your partner will need to be a bit creative in order to add details that are interesting, while staying at your level of proficiency in terms of grammar and vocabulary--the details should not themselves become the focus of the sentences, requiring much repetition for you to remember them. They should be made mostly of grammar you already know. Or if she adds it and you later forget it, then just don't worry about keeping it in the sentence.
Whatever you choose to do, good luck. And remember, comprehension far outpaces production.
.
