Hi Sashank,
At your scoring level, the GMAT becomes really "sensitive" to silly/little mistakes, so you have to take a good look at the questions that you're getting wrong and figure out WHY you're getting them wrong.
Here's an exercise that you can do to assess what you're missing: Review your last CAT and take a good look at all of the Quant questions that you got wrong. How many of them were due to a silly/little mistake? How many of them were because the question was just too hard? To pick up those missing points, you have to eliminate the silly mistakes and nail the "gettable" questions.
With one week to go, there probably isn't much else that I can recommend. You've developed a way of "seeing" (and responding to) the GMAT that probably cannot be changed in such a short period of time. It might be that "your way" of doing things is why you can't score above a Q48. If you can find (and fix) those little mistakes though, then you could improve this score.
GMAT assassins aren't born, they're made,
Rich