Did you take the GMATPREP before your GMAT attempts ?And if yes, how much did you get on them ? As a matter of fact, the GMATPREP tests correlate closely with your performance on the actual tests. Also the Verbal section on the GMAT is trickier than those on the Kaplan tests. Most of the questions in the Kaplan tests are reworded versions of the questions on the OG.

The bigger question to ask here is not how much did you get on so and so exam but how much strong were you conceptually? Going by your Verbal scores, it's not very difficult to see conceptual clarity. You'll see a lot of stories here of people saying "I practiced blah blah number of questions on Verbal,yet landed up with a bad Verbal score".
Achieving a 650 would require an absolute clarity of concepts and the ability to apply those concepts well. When do you plan to take the GMAT, by the way ?

I agree with Rishi. Take a GMATPrep and spend time understanding why you scored low. There are typically 3 reasons. In you case it could be a combination of all 3!

1. Not knowing the underlying theory - this is basically knowing the basic rules of grammar, formulae in quant, question types in CR etc.

2. Not having a proper approach - do you know how to approach a assumption based CR question, what strategy do you applying quant (plugging values, working from answer choices, estimation etc), doing the vertical split in SC.

3. Not able to keep nerves during the test - essentially lack of practice leading to low mental stamina OR getting flustered on the actual test and not being able to manage your time well.

Think about it and make a strategy around it.

Arun