Hi Yesh369,
Many GMATers spend 3 months (or more) of consistent study time before they hit their 'peak' scores, so if you are going to limit your studies to just a little more than 6.5 weeks, then there will likely be a limit to how much you can improve. In addition, assuming that you took this recent CAT in a realistic fashion (and this 590 is an accurate assessment of your current skills), raising a 590 to the point that you can consistently score 710+ will likely require at least another 2-3 months of consistent, guided study - and you'll have to make significant improvements to how you handle BOTH the Quant and Verbal sections. Thankfully, the GMAT is a consistent, predictable Exam, so you CAN train to score at a higher level. That having been said, with just a little over 3 weeks of study time, that type of score improvement is probably too difficult to be considered realistic.
Before I can offer you any additional advice for your studies, it would help if you could provide a bit more information on how you've been studying and your goals:
1) What study materials have you used so far?
2) Is this the only practice CAT that you have taken so far? On what 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)?
3) 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