To push back or not to push back???

So, my experience thus far in GMAT land is a fairly short, yet steep road...i initially thought i could study for about 6 weeks or so and come close the the 680 or so that i need to get into Anderson. But was quickly disturbed by my cold turkey OG and PR CAT test scores. Basically all in the 520 - 560 range. After 3 weeks of studying, I feel somewhat better, but haven't seen the improvement in my test scores.

I realize after reading the posts on this site i've been going about it all wrong...focusing on PR and Kaplan...haven't even opened the OG. I thought I could study for around 5-6 weeks and prepare enough to get a 700, but am quickly finding that not be the case. I only have 2 1/2 weeks left to study before my test and am now considering rescheduling.

However, i've talked to several friends and they said not to reschedule and look at my first GMAT test almost as a kind of "practice test" knowing that it will help to prep me for my "real" 2nd test. I know that people get "lucky" on test day and see questions that favor them, but if my goal is to get at least a 680...and i'm scoring ~580-620 on the PowerPrep tests pre-test day...should i go through with it or should i just reschedule when i know that i'm more prepared?

Rgds,
J