Hi bl12345,
You ask a broad question, so I would suggest that you do some research, visit the various GMAT company websites and gather the necessary information. There are plenty of options when it comes to preparing for the GMAT (classes, self-study, tutoring, etc.). Most GMAT companies offer some type of free resources (practice problems, Trial Accounts, videos, etc.), so that you can "test out" a product before you buy it. I suggest that you take advantage of all of them, then choose the one that best matches your personality, timeline and budget.
1) How many hours do you think you can study during a typical week?
2) When you took this CAT, did you take the FULL CAT (with the Essay and IR sections)?
GMAT assassins aren't born, they're made,
Rich