Well, the good news is that you are in a great position and off to a very good start. You neglected to write WHICH degree you wanted (MFinance, I assume), and I think that with your grades and superb involvement you should definitely have a shot at the top finance programs (Princeton still leads the pack)
As for your GMAT - I'll give you the tricky answer - As much as you can get! Above a 700 is best, and above 720 better.