Hi snfuenza,
You could certainly do some 'concept work' before starting your Course, but that work might not be necessary - and it might end up costing you a bunch of time that might be better spent on other areas. Defining your timeline in a bit more detail would be useful at this point. You stated that you'd like to (hopefully) take the GMAT before August, so would you rather study consistently for 3-4 months or for a longer, more drawn-out period of time (such as 6 months)? In addition,
1) What is your goal score?
2) When are you planning to apply to Business School?
3) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich