Hi sshad,
Depending on the specific EMBA Programs that you are interested in, you might have the option to take the Executive Assessment (EA) instead of the GMAT. The EA is essentially a 'mini-GMAT'; it's shorter, easier and would likely take you far less time to prep for. As such, you might want to research whether the Programs you plan to apply to accept the EA as part of the application process or not.
It sounds like you've given your whole situation some thought before you begin your studies, which is good. For free math practice and help, I recommend that you set up an account at Khan Academy (
www.khanacademy.org). The site is completely free and makes the learning a bit more fun and 'game-like' (as opposed to the dry academic approach taken by most books). While the site is vast, you should limit your studies to basic Arithmetic, Algebra and Geometry. After spending a little time re-building those skills, you can start your GMAT studies.
Before I can offer you any additional advice for your studies, it would help if you could provide a bit more information on your timeline and your goals:
1) What Schools are you planning to apply to and when are you planning to apply?
2) What is your overall goal score?
GMAT assassins aren't born, they're made,
Rich