Hi paidlukkha,
Before I can offer the specific advice that you're looking for, it would help if you could provide a bit more information on your studies so far and your goals:
1) How did you score when you took the GMAT (including the Quant and Verbal Scaled Scores)?
2) How long did you study before that attempt?
3) What materials did you use?
4) What is your goal score?
5) When are you planning to apply to Business School?
6) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich