Hi adukeshav,
Each School/Program has it's own Admissions Deadlines, so you should visit the website for each School to get THAT information. Putting together a strong overall application takes times - many Test Takers spend MONTHS working on the various pieces of the applications. You also have to factor in the time that it will take to properly prepare for the GMAT. Most Test Takers spend 3 months (or more) on their studies before taking the Test. You can take the GMAT more than once, but you have to wait 31 days between Tests, so THAT is also something that you have to factor in.
If you have the time and you're thinking far enough ahead, you would probably find it beneficial to focus on the GMAT first (re: now), so that you can "lock in" your score without having to work on everything else at the same time.
GMAT assassins aren't born, they're made,
Rich