Happy new year everyone!

I am in the process of preparing for my GMAT and would like to practice using some high level questions. I am aiming for a 750 if possible, and have booked for the test towards end of Feb 2012. I've finished the entire OG 12 but I am going to relook @ it one more time. Can someone please direct me where I can get such questions? Hopefully, the questions should come with answers and explanations.

Many thanks in advance!