From my point of view, you have decent level of quantitative. However, do not let your strength become your weakness; you should spend some time reviewing theory and doing some problems. May be 4 hours for quant per week is enough (in period of intensive verbal practice..)
For SC:
MGMAT SC is the key to success. Read theory, do the problems at the end of each chapter and return to the theory if you get wrong. Practice makes perfect. SC is pattern; the more you do, the more you will be proficient so that you can spare time for CR and RC.
Other good material are SC Grail and our forum's resource :
gmat-grammar-ultimate-by-gmat-club-102387.htmlFor CR: I choose CR bible. The structure of the book is clear and its explanation helps me a lot.
RC: Reading, reading, reading.... I prefer magazines to fiction because it's up to date and I think that their contexts are similar to those of GMAT. However, you may prefer fiction :D. Your choice. Try to get the main idea, the tone and the structure while reading.
Hope it helps....