Hi prakharsworld,
On a fundamental "level", most Test Takers who can score a Q49 should be able to score a Q50 or a Q51. As such, while there might be a few 'upper-level' areas where you could use some practice, those areas are probably NOT what would generate the missing Quant Scaled points that you're looking for.
Take a good look at whatever CAT you scored Q48 or Q49 on... of all the questions that you got wrong, how many were due to a silly/little mistake and how many were due to the question being too 'hard'? How many of those questions were 'gettable' and how many of them were just too much for you to handle?
If you find yourself saying "I should have gotten that one correct..." a few times, then THOSE are the questions that cost you your points.
GMAT assassins aren't born, they're made,
Rich