Hi Shrug650,
While having the proper RC 'skills' will make a big difference in how you handle the Verbal section (and the score that you earn), a V21 means that you lost LOTS of points in ALL 3 major Verbal categories (SC, RC and CR), so you would benefit from improving in any of these areas.
Before we can talk about how you should study for the next month, I'd like to know more about your studies so far and your timeline.
1) What resources did you use during your initial studies?
2) What 'steps' do you use when dealing with a typical SC, RC or CR prompt?
3) Did you have to rush to finish the Verbal section on Test Day (and how many questions did you have to guess on)?
4) When are you planning to apply to Business School?
GMAT assassins aren't born, they're made,
Rich