Hi kamkaul,
Since it's been 2 years since you took the GRE, it's likely that some of those skills have 'faded' over time. Thus, it would help if we had a more recent GRE performance to use as a basis for comparison - so you should plan to take a FULL GRE MST sometime soon (you can download two for free from
www.gre.org). One of the challenges that you're going to face with your timeline is that even if you took an Official Exam at the end of September (whether it's the GRE or the GMAT), you wouldn't have any more than 7 weeks of potential study time, which might not be enough for you to hit your score goal.
1) Are you planning to re-apply to the each of the Schools that you listed? Have you contacted each School to determine how much of the re-application process is even necessary (if they accepted you once before, then they might just need an updated profile to confirm that you're still a strong applicant - and grant you admission)?
2) Are you planning to apply for a Scholarship? What is the GRE/GMAT score 'requirement' for those scholarships?
GMAT assassins aren't born, they're made,
Rich