if you read through some of the posts on here you'll see many helpful study material, A common study aid is the MGMAT study guides, which I found really helpful. Especially the Setence correction study guide, it costs rougly $25 but its worth it.
Also, right now I am reading the Powerscore GMAT Critical Reasoning Bible, which I am finding pretty helpful as well...although its a bit lengthy (300+ pages)
I would review the OG over and over, if you can conquer the OG verbal
, then your verbal should be set to get the 630 you need...
As for Math, I am biased since I took the MGMAT class
, but I did like the MGMAT strategy guides as well as the online exams for practicing Math...