I feel for you dude - math has always been a tough subject for me (took lots and lots and lots of math courses at a good university, always did average). I just don't "get" math - I look at it and it's all greek to me.
I'm lucky in that I don't have the same issues with the verbal sections. Never studied, scored 99th percentile. Writing simply makes sense.
I scored a 650 the first time I took the GMAT, after scoring somewhere in the 45th percentile on the quant section. I used the Kaplan GMAT Review book and did all the math problems over again...managed to move the math score up to the 68th percentile - enough to score a 700.
Just remember in the end that they always end up asking you the same kinds of problems, just from different angles.