Two and a half weeks to prepare . . .

I was already getting registered for an MBA program here in my home town where I was able to waive the GMAT due to my undergraduate grades. A recent job offer has thrown a wrench, a good one, into the situation. I know have about three and a half weeks to apply to 3 or 4 other MBA programs nationwide and my only option to take the GMAT was January 8th. It is currently December 23 so that gives me, in reality, about 2 weeks to prepare. Any advice on quick test preparation? I've been very good at standardized testing with high ACT and SAT scores but i've never actually prepared for a test. Any advice would be greatly appreciated! Thank You!