Hi Marco,
Before I can offer any suggestions, I'd like to know a bit more about how you've studied so far over these last 3+ months:
1) What resources have you used?
2) How did you score on each of your CATs (including the Quant and Verbal Scaled Scores)?
3) Did you take the FULL CAT each time (including the Essay and IR sections)?
4) What were you Quant and Verbal Scaled Scores for your Official GMAT?
Thankfully, the GMAT is a predictable, standardized Test, so you CAN train to score at a higher level. While you will probably need some new study resources, you won't necessarily need a Tutor.
GMAT assassins aren't born, they're made,
Rich