Hi AinzOoalGown,
Many Test Takers who use a 'book heavy' study approach end up getting 'stuck' at a particular score level, so you might end up needing to invest in some non-book resources to hit your Score Goal. The OG books are great sources for practice questions, but they're not designed to teach you Tactics, patterns or the little 'secrets' behind the GMAT - for those, you'll need Course-oriented materials.
Before I can offer you any additional advice, 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 study materials have you used so far?
3) How have you scored on EACH of your CATs (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
4) What is your goal score?
5) When are you planning to take 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