Hi junii,
If you are looking to score significantly higher on your next Official GMAT, then we'll need to make sure that you are focused on honing the necessary skills. If you just end up working through sets of practice questions in the same ways that you did before, then you will likely continue to score at the same general level. Thankfully, the GMAT is a consistent, predictable Exam, so you CAN train to score at a higher level.
I'll be happy to help you plan out this next phase of your studies, but we need to better define how you have been studying up to this point:
1) Did you take the At-home GMAT or did you take your Exam(s) at a Test Center? On what dates did you take each of your 3 Official GMATs and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
2) What study materials have you used over the course of ALL of yours studies?
3) Over the last 3 months, on what dates (or approximate dates) did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
4) When are you planning to apply to Business School and what Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich