Since you are clear about your aspirations 2-3 years prior, you are in a much better position than most of the Indian (Non-natives) GMAT aspirants. As much as i have seen, people like us who start from ground zero level give exam with a preparation of almost an year. We suffer NOT because we don`t have intellect to solve questions asked in GMAT like exams, but because we underestimate ourselves. Also, we have a very weird aversion towards READING and SPEAKING good English and lack exam temperament (talking about average Indian aspirant. If you are not one of them then its an added advantage for you).
I have been preparing for GMAT from past 6 months (believe me i was damn bad in English). If i were in your position, I would not buy
MGMAT books NOW. Rather i would concentrate specifically on good GMAT kind READING HABITS (You will get a lot about GMAT reading habits on this forum). This will benefit you in many ways: you will be confident while reading long passages, your concentration level will increase, your analytical skills will increase exponentially, you will reduce time taken to solve questions. You will find many more benefits once you start doing it diligently.
Once you gain confidence in reading, start solving few Reading Comprehension problems (there are so many sources available on this forum itself). At this point in time you can move slowly to Critical reasoning.
You must be thinking why i am putting more stress on RC and CR?
I am suggesting you with my experience. People who are very good in RC and CR score much better in GMAT than an those who dedicate a big chuck of time on SC. Above all, SC can be appropriated in few months, but RC and CR cannot be. It takes time. You will realize this as your preparation will mature with time.
So my friend, read good English, read articles from good sources, while reading also see the sentence construction and get habituated with them.
I did not suggest anything for Quant because i had not suffered because of Quant as much as because of English. You can decide on Quant part based on your comfort level in Maths.
Hope this helped....