Hi thibaut27,
To start, a 620/Q49 is a decent score - depending on which Schools you plan to apply to, this score might be enough (when combined with a strong OVERALL profile) to get you in. You've defined your timeline, but I'd like to know a bit more about the work you've done so far and your goals:
1) How long have you been studying?
2) What resources have you used so far?
3) When are you planning to apply to Business School?
4) Do you know which Schools you plan to apply to?
We have a variety of free resources at our website (
www.empowergmat.com) that you can use to 'test out' the Course before you set up a Full Account. If your Quant Scaled Score is consistently Q49+, then you have a much greater opportunity to pick up points in the Verbal section. Depending on how much time you have available to study during a typical week, you might be able to do some intense study over the Course of a month (with the EMPOWERgmat Verbal Score Booster) and raise your score to 700+.
GMAT assassins aren't born, they're made,
Rich