GMATPrep is a practice exam (well, 2, actually) offered for free by the people who make the official test. You can download the exams from
www.mba.com. Definitely get those, though you should know that those exams do not offer explanations for the problems, nor will they show you how much time you spent on each question. You'll have to use a stopwatch yourself to keep track (which you should do, as that's important data to help you improve!).
You can find explanations for a lost of the questions in the two GMATPrep folders here on the forums. Search for a problem to see whether it's already there; if not, you can post it yourself.
How often are you taking practice tests? It's not typically useful to take them more than once a week, and it's actually better to go closer to 2-3 weeks before taking another. CAT exams are really good for (a) figuring out where you're scoring right now, (b) practicing stamina, and (c) analyzing your strengths and weaknesses. The actual act of just taking the exam is NOT so useful for improving. It's what you do with the test results / between tests that helps you to improve.
There are a lot of different combinations that add up to a 700. You need to be able to score at least a 36 or 37 on verbal and at least a 39 or 40 on quant. (Though those are the bare minimums if you maximize the other score; a combo of those two figures will be closer to 600 than 700.) If your quant stays around 47, you'd probably need around a 40 or low 40s on verbal.