Hey RT,
So congrats on the fantastic GMAT!
You have a very nice profile so far. A great GMAT, an NIT grad with very good grades, and what looks to be very good work experience (need more detail here).
I think if you apply next year with 36 months of work already in the bag, it should be enough and you would not need to wait any more. I'm right now missing a bit of current community service/volunteer work, so you might want to think about adding something there. The ideal is something that is well known or something where you can take some leadership.
Top 3 are going to be tough (they are for just about everyone, it's only easier if you have something totally totally exceptional in your profile), otherwise, I'd expand that list to Top 15 (to play it safe) but with a good application and great essays, you should be able to get into an excellent program.
All the best,
Jon