Valencia - I am not sure if three weeks are enough to cross 700. I am sorry if my words are not comforting. I know you are extremely stressed, and this is the last advice you were hoping for here. According to my experience, the last two weeks should be used strategically. It's not the time to build new concept. You need to focus on your strengths in last two weeks. Review idioms, notes, and logs. Take a couple of tests ( includding GMATPrep 2). So you are left with only one week.
Since you are able to achieve above 670, the journey becomes tough as you start approaching 700. You will find tougher CR, RC and quant problems. The structure will also be different if the system thinks that you are doing better and are a potential 700 candidate. For example, in my experience, if you get EXCEPT inference question in RC, you can bet that you are doing much better in verbal. As you are approaching 700, you need to focus on concepts and strategy.
Also, you have not mentioned your GMATPrep score, which predicts your performance. More than any test, GMATprep is a reliable indicator to predict your score. All the best!!!!