Hi mehditarbouu,
A strong GMAT score can certainly help to compensate for a 'weak spot' in your application, but it's not the only aspect of your application that you can strengthen 'relatively quickly' (strong Essays and/or a strong Interview can also greatly improve the strength of your Overall application). In addition, you might consider taking a College-Extension Calculus or Statistics Class. Scoring at a high level in those types of classes would show Admissions Committees that you CAN handle the 'academic' side of their Programs (and those math concepts are relevant to the work that you'll do in most Programs).
You're ultimately asking Admissions questions though, so you would likely find it beneficial to speak with an Admissions Expert about your overall profile. There's a Forum full of them here:
https://gmatclub.com/forum/ask-admission ... tants-124/1) How long have you studied?
2) What study materials have you used so far?
3) How have you scored on each of your practice CATs (including the Quant and Verbal Scaled Scores for each)?
4) What is your goal score?
GMAT assassins aren't born, they're made,
Rich