Hi TigeronFire,
Each Official GMAT that you take provides its own score for Quant, Verbal, Essay, IR and Overall Score. Thus, 'combining' individual pieces from multiple GMAT scores does not occur. Most Business Schools don't care if you take the GMAT once, but it's unlikely that a School will use your 'best pieces' from multiple Exams. As such, you have to train to put together a strong OVERALL performance in one go.
From what you've described, it sounds like you've taken the GMAT at least once already. Before I can offer you the specific advice that you’re looking for, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long have you studied?
2) What materials have you used?
3) How did you score on the Official GMAT (including the Quant and Verbal Scaled Scores)?
Goals:
4) What is your goal score?
5) When are you planning to retake the GMAT?
6) When are you planning to apply to Business School?
7) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich