Hi sagnik242,
Thankfully, your score goals are reasonable, but you're going to have to make some significant improvements to how you handle the Quant section to hit that goal.
Your studies so far have been 'book-heavy'; many Test Takers get 'stuck' when taking this type of approach, so you might have to invest in some non-book study resources.
I have a few questions about your studies so far:
1) How long have you been studying?
2) When you took the GMAT, did you have trouble finishing the Quant section on time (and did you have to guess on a bunch of questions just to finish?)?
3) What type of deadline are you facing?
GMAT assassins aren't born, they're made,
Rich