Why can't I have more than 6 Relpax a month when thats the only thing that works for me?

I have had bad head aches every since I was a little girl but only in the last seven years have they been diagnosed as migraines. I have tried to find the triggers but have not been able to do so. When the dr. asked me about my aura, my reply made her look at me as if I was two headed or something. My aura is a pain in my right elbow. It sounds funny but is very painfull. After this I end up with a kind of "stupid" feeling. Then most of the time I end up in bed  and alot of time throwing up. My frustration is that my dr. and I have found a pill that helps avoid all this. But for some reason she will only let me have six a month. This is by far to few. If I am supposed to take this pill at the first sign of a migraine, these pills go fast. She has put me on Topamax but they do not seem to be working yet. Sometimes I get that feeling like they will never get better. Anyone ever feel that way too?