We are happy to hear that you had an improvement in both portions! We just had a student last week that reported that she went from a 510 to a 740. With that being said, YES, going from a 530 to a 650 is indeed possible.
It sounds like you already know where you need improvement. Since you have your timing down, we suggest to focus on the problems that you listed in your forum post ( data sufficiency and critical reasoning questions) and go through the Official Guide problems.Here are a few resources that we recommend to our students while they are studying:
Forums/Resources (you can search problems you are looking for)http://www.facebook.com/VeritasPrep?sk=wallhttp://www.veritasprep.com/blog/http://www.beatthegmat.com/http://gmatclub.com/
1.The Official Guide for GMAT Review and the Official Guide Verbal Supplement (for additional practice problems)
2. A book called “Grammar Desk Reference” (by Gary Lutz and Diane Stevenson) for good, targeted grammar reference
1. The Official Guide for GMAT the Official Guide Quantitative Review (for additional practice problems)
2. Short-Cut Math by Gerals W. Kelly
Good luck with your studies, we hope you achieve your GMAT target score of 650!
Jenny & The Veritas Prep Team