Hi malyaj,
When you use the phrase "crash course", are you looking for a GMAT Course that you can complete quickly? I ask because that is probably not the best approach for you to train for the GMAT. Many Test Takers spend 3 months (or more) of consistent study time before they hit their 'peak' scores, so - depending on your score goal - you might want to consider other study options.
1) Have you done any studying so far for the GMAT?
2) What is your goal score?
3) When are you planning to take the GMAT?
4) When are you planning to apply to Business School?
5) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich