GMAT Strategy

I've just completed a MGMAT course 2 weeks ago and have since been rigorously studying. I just completed my third MGMAT CAT Test and I scored 520 - a complete and utter disappointment. For my first 2 tests, my scores were 480 and 530 respectively. I am taking my exam in two weeks and I'm wondering if anyone can suggest anything I can do to drastically improve my score? I was aiming for 650 and above (700)... yet that goal seems extremely elusive right now. I've been working hard and I understand all the material in the MGMAT books and perform well when I'm completing questions from the OG12... so it's very frustrating for me that I'm not producing good results on these CAT tests. How well do the MGMAT CAT test results compare to how well people score on the actual GMAT? Should I reschedule? Or is there a chance that I will perform well in 2 weeks time?
Thanks for your help!