Research MBA Programs

I am 39, self employed, BS Computer Science)/Masters GPA 3.1/4.0, 17 years of work experience in IT consutling, recently taken GMAT (Score 600 - disappointed!). I plan to apply for the EMBA program at Booth Chicago and am concerned about the following.

1. Fact that I am self employed
a. Would be difficult to project my work
b. Cannot produce a reccommendation from superior (Is it smart to get letters from past clients?)
2. GMAT score, though not required is lower than expected for a reputed school
3. Difficulty I am facing with my essay
a. Sincerely I need an MBA to help myself be a better manager, seems like a simple a goal, yet hard to sound convincing.

Experts, I need some sound advise and frank assessment of my chances with this profile.

Thanks in advance!