Kaplan tests tend to score low. More in depth analysis of your verbal scores is needed to determine what approach should be take with them. i.e. - are youa native speaker, what questions are you having problem with in verbal, and are you running out of time at the end?

That being said, of course you can improve your verbal score, but the real question is how much can you improve it by? I will say that a 2 pt increase in your verbal scaled score will have a greater impact than a similar increase in math. With you scoring close to max on your quant, a more focused effort on verbal will net higher yields for your overall score.

Those aren't really "low scores." It really depends on which school you want to go to. But if you score 650 and have a strong GPA, you shouldn't get yourself too stressed out.