The first thing to do is to take at least one week off from any GMAT study. You probably studied for a while, so you deserve and need a break.
During this time, I also advise you to read the content in the following links:
should-i-retake-gmat-thread-retaking-gmat-strategies-83339.htmlbest-gmat-verbal-prep-books-reviews-recommendations-78094.html?highlight=ml308As sandeep800 suggested, look into Manhattan SC and Powerscore CR. Those are the most popular books for verbal. If you need extra help in RC, I encourage you to practice with LSAT RC questions. For some, an RC guide is also recommended. Options include Powerscore RC or Manhattan RC. However, RC guides are usually not necessary.
If you have a little extra time, also consider some
GMAT Fiction. This is an enjoyable way to improve your RC and SC skills.