Yes, your timing problems likely did cause a significant drop in your score, especially as you had a large number of wrong answers clustered towards the end of the test.
First, 7 Aug is about 3 weeks from now. Your scoring level is currently in the high 500s. It would be very difficult to achieve a jump to 700 in 3 weeks. I'm not sure that I've ever spoken with someone who was able to achieve that kind of score increase in that timeframe. I would advise that you decide whether you would rather take the test on 7 Aug, but lower your goal score, or whether you would rather postpone your test and still go for the 700+ score.
Your percentage correct is generally not a useful figure with which to analyze your performance - especially without data about your timing or the difficulty levels of the problems. It's all inter-related. If someone gets half of the SCs wrong, but the SCs were all 700+, then that's not really a bad performance.
Similarly, you report getting a greater percentage of PS correct than DS, but how was your timing on each of those categories? I often find that people who think they're bad at DS aren't actually bad - they're just spending a lot more time on PS, so they're then forced to rush on DS, and their DS performance suffers as a result. Check to make sure that's not what's happening with you.
I can't advise you specifically because the data given above is not adequate to understand your specific strengths and weaknesses. Generally speaking, it is very difficult to use GMATPrep to analyze your strengths and weaknesses thoroughly because GMATPrep, while a very good test, does not provide the necessary data to analyze your full performance.
I would suggest that you take a practice test that does give you more data. You can sign up for a free test with us, if you'd like. If you do take our test, then you can use the following article to help you analyze your test results:
http://www.beatthegmat.com/a/2009/09/23 ... tice-testsThen, you can come back here to share the data and analysis, and we will help you figure out what to do with that information.
You may also want to read this article about developing a study plan:
http://www.beatthegmat.com/mba/2010/02/ ... study-plan