Hi swabawe,
If you've been studying for the GMAT in a relatively consistent fashion over the last several months (since you took your 1st Official GMAT), then shifting to the GRE might not be the best choice. Much of the content that you've learned for the GMAT would translate over to the GRE (although the GRE does place a far greater emphasis on your vocabulary knowledge - and when to use certain words instead of others - so you would have to put in some time to build up your vocabulary). Before you shift to a different Exam, it would help to know a bit more about how you've been studying as well as your timeline and goals:
1) Since you took your 1st Official GMAT, on what dates did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
2) When are you planning to apply to Business School and what Schools are you planning to apply to?
If you're interested in taking a free practice GRE, then you can access 2 for free from
www.gre.org.
GMAT assassins aren't born, they're made,
Rich