Hi ayan1304,
With about 4 weeks to go, you really have to make sure that you're taking your CATs in a way that 'matches up' with what you'll face on Test Day. Thus, you have to take the CAT in a realistic and test-like fashion, including taking the ENTIRE CAT (with the Essay and IR sections), at the same time of day as your Official GMAT, away from your home, in a test-like environment and NOT do anything unrealistic.
If you want to focus on the Quant section for these last 4 weeks, then that's fine, but you shouldn't 'abandon' your Verbal studies entirely - you're going to have to do some work in that area to keep your Verbal skills sharp. By focusing on just the Quant, there will be a limit to how high you can score overall.
From what you've described, you've been using a "book heavy" study approach. Unfortunately, many Test Takers get 'stuck' at a particular score level when studying in this way. Even the best books are limited in what they can teach you; they also can't force you to approach questions in a certain way and their explanations are often one-sided. This is all meant to say that you might want to consider investing in some new non-book resources. With Quant Scores in the low-40s, you're making some little mistakes throughout the Quant section AND you're missing out on lots of 'strategy-based' points.
1) How many hours do you think you'll be able to study each week going forward?
GMAT assassins aren't born, they're made,
Rich