Hi Ashay,
You appear to have given yourself plenty of lead-time before you actually "need" your GMAT Score - which is great. This provides you with a great opportunity to hone your general 'math' skills without having to spend much - if any - money.
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.
Beyond that, while the
OG books are great sources for practice questions, they're not designed to teach you Tactics, patterns or the little 'secrets' behind the GMAT - for those, you'll need Course-oriented materials. As such, you might want to work on the
OG a little later on in your studies.
As an interim step before fully-committing to a GMAT Study Plan, I suggest that you work on your math skills for a couple of weeks, then review your first CAT. We'll be looking to see how many of those Quant questions you could get correct (with your newly re-learned math skills). That should also help to define the other areas that you will need to work on going forward - and the type of Study Plan that you should follow.
If you have any additional questions, then you can feel free to contact me directly at any time.
GMAT assassins aren't born, they're made,
Rich