What do I do now?

Presently,I am a graduate school student at large at Chicago Booth.I was just denied admission and started my first class during the admission process. I had a bad day on the GMAT (it was loud and distracting at the test site) scoring a 630 45Q and 31V in which the main problem was that I ran out of time with both sections. I have an undergrad GPA of 3.4, and a grad GPA with 25 hours of credit in a MBA program at major university of 3.64. I have 15 years of managerial experience at a large corporation with a natural progression of advancement. Should I bother retaking the GMAT or should I concentrate on obtaining a killer grade point in the three classes that I am allowed to take for credit ? What would be my best approach in acceptance at Booth or Kellogg? What are my chances of acceptance if I perform well and how well do I have to perform? How many times should I try and when should I consider Purdue Krannert?