Let's see. First, great job on quant. :) I know you want a better score on verbal, but just wanted to say that.
Next, should you take the test again in one month? Probably not, since you want a 100+ point improvement - that's probably going to take longer than a month.
You mention scoring a 680 and 660 during the week before the actual exam. Why do you think you scored higher on the practice tests? Did you do the practice tests under 100% official conditions, including essay, IR, length of breaks, etc? Did you give the same level of effort to essay and IR as you did on the real test? If not, then mental fatigue may have been a problem on the real test, especially for the last section (verbal).
What did you do in the last few days before the real test? Did you take practice tests? Did you study a ton? Again, you may have fatigued yourself too much in the last few days.
Did you experience anxiety? Trouble sleeping the night before? Trouble concentrating during the test? Etc.
That can all help us to figure out how / why you fell short, which will help us to know what to do for next time.
Next, you've said that you want to score 700+ but your practice tests weren't that high, so there's also some work to be done to lift your score further.
For more specific advice about what to do for verbal, I'd like to get some more detailed data on your strengths and weaknesses in order to advise you. Use the below to analyze your most recent MGMAT CAT(s):
http://www.manhattangmat.com/blog/index ... ice-tests/Then come back here and tell us the results of your analysis and what you think you should do based on that analysis. (Note: do share an analysis with us, not just the raw data. Part of getting better is developing your ability to analyze your results - figure out what they mean and what you think you should do about them!)