Please spend at least twos third of your available time on RC and CR. You don't have to do tons of questions, but should understand articles thoroughly and get used to the question types. Most important, know why you mistake and summarize! Moreover, do simultaneous tests every week to build the scene of pace.
In my opinion, you should not give up CR and RC since every section is to test your reading ability. Math section is easy for us if you know what it ask. Some hard SC questions depend on your comprehension of their meanings. If you spend more time on your weak point, you have better chance to achieve your goal. Moreover, during the test, your performance on SC will be influenced by the other part of section. In sum, Don't give up RC and CR
If you can get 580 at Tofel, I'm sure you have the ability to meet your goal. I'll take the test too during late December, be persistent and good luck.