With a score of 26 in verbal, I don't think that a crash course will do much good. It would be much, much better to review a guidebook. But if you still want to take this path, then look into LSAT passages for RC, the Brutal SC Document and Aristotle SC question bank for SC, and perhaps some LSAT questions for CR.
You actually don't need to improve your math performance. In fact, doing so might actually eat up valuable time spent on verbal. The verbal section is the area that contains the most room for improvement and the most points for you. With that said, Jeff Sackmann's Extreme Math Challenge
, while expensive, is a good source. The GMATClub tests
also contain upper-level math problems.