Hi Mariana86,
I'll be happy to advise, but I'd like to know a bit more about your studies and timeline/goals:
1) What is your goal score?
2) When are you planning to take the GMAT?
3) When are you planning to apply to Business School?
4) What were your Quant and Verbal Scaled Scores on each of these CATs?
5) Did you take the ENTIRE CAT each time (including the Essay and IR sections)?
6) Do you have trouble finishing any of the sections on time (and do you have to guess on questions just to finish?)?
GMAT assassins aren't born, they're made,
Rich