I-140 approved, 6+3 H1b ext; thinking of an MBA

[hkumar1]

Hello, as the headlines says I have my I-140 approved(PD Dec 2010) and have applied for 3 years extension on my H1B visa(1st 6 years expired). I am thinking about joining a part time MBA program and hoping to graduate by Dec 2013. Having applied for GC in the EB3 category, I am not confident that my PD will be current by end of 2013. My concern is that I do not know how that H1B extension works after the 6+3 years extension. Am I eligible for extension after that and if so for how many years?
Appreciate you help in this regard. Thanks in advance.

[txh1b]

You can get 3 year increment extensions as long as you have an approved I140. I am not sure what significance the MBA has at all in your post.