Well it all depends on what kind of score you are looking at.
47+, I recommend the Challenges and
MGMAT Quant. They are much more difficult than normal Gmat test problems. But honestly, don't go crazy w/ perms/combinations/prob/distance-rate/stat (mean & median) nonsense. Intuitively understand these concepts. Challenges and
MGMAT, I feel really take these types of problems to the next level. But if you're looking only at getting a 45-47 Q, you can do so by eliminating stupid mistakes and get your basics down cold. Focus on number theory, geometry, know how to manipulate fractions, decimals, etc. Finding quicker ways of doing mundane problems. Gmat tests speed and accuracy exclusively, it is not a final exam in Discrete Mathematics.
Spend your extra time on Verbal. Most people kill themselves on the Q and severely under prepare for Verbal. Yes, its nice to get above a 90% in Q, don't get me wrong, but not at the cost of your Verbal score. Display your prowess on both portions of the test. No one wants to be known as the guy who can only crunch numbers. If you look at any top 20 B-school's class snapshot, you'll notice that everyone has a much higher V score than Q. hmmm..