What is my GMAT standing

Hi,

I have my GMAT in around 28 days. However, I am not sure of my actual GMAT standing yet. Can you please help me know that. Below are the scores from the various tests I have taken.

1. Princeton Review test 1 | 18/05/2013 | 550
2. Princeton Review test 2 | 01/06/2013 | 610
3. GMAT Prep 1 | 07/06/2013 | 650
4. Princeton Review test 3 | 28/06/2013 | 570 ( gave this one in high fever)
5. Princeton Review test 4 | 10/07/2013 | 630
6. Kaplan test 1 | 13/07/2013 | 670
7. Kaplan test 2 | 18/07/2013 | 640
8 . Princeton Review test 5 | 21/07/2013 | 710
9. Kaplan test 3 | 25/07/2013 | 640
10. Princeton Review test 6 | 28/07/2013 | 650
11. PowerPrep test 1 | 28/07/2013 | 720 ( but a lot of questions where OG repeat)
12. GMAT Prep 1 | 04/08/2013 | 700
re-take (after a month gap).
Got 5 questions repeat in quant , got 3 of them wrong again.

I simply am not able to gauge my performance till now. My target score is 750. Should I consider re-scheduling my exam?
I am really scekptical about re-scheduling because the 1st school I want to apply to has deadline of 15th Sept,2013.