Hi,
I am writing here because I stay interested in recent GMAT activity. I did mine some years ago and currently attend a European B-School.
I can recommend the books of Manhattan GMAT, esspecially for maths exercise. They are really hard and therefore good to prepare for a high score. Furthermore I did a course in Bavaria, Germany that was really inexpensive and helpful.
Check out, http://www.gmat-workshop.de
It absolutely good value for the money.
All the best to you,
gmat2204.