Why is your score bad? A 680 is quite good, while the verbal and quant scores are balanced. See this link for guidance on a retake: should-i-retake-gmat-thread-retaking-gmat-strategies-83339.html
As for materials to overcome the specific topics that you mentioned, Manhattan has guidebooks on those subjects. Also look into Jeff Sackman
's math sets for practice problems on those areas.
And you should absolutely spend time on verbal beyond reviewing. Always try to adopt an aggressive, active mindset toward the GMAT. The way that you phrased your prospective verbal strategy - to "simply review" - makes it sound like you plan to passively go through the motions. This can get you into to trouble.
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