Extremely low GPA. Can I still get into a top school?

[unforgiven]

I have decided to pursue an MBA and want to know what my chances are moving forward. To the say the very least, I had a turbulent undergrad and graduated with a commerce degree (2.3 GPA) from a top school. I have 4 solid years of work experience and intend to do well on the GMAT. If I am able to score above a 700, will this be enough to offset my very low GPA? I want to know my chances moving forward. Am I still a candidate for a good MBA program or am I wasting my time. To help mitigate the GPA, I have considered taking university courses and getting A's. In the time since graduating, I have volunteered as a board director for two non-profit organizations and am well travelled. Not sure if worth mentioning, but am also a visible minority. Any input is appreciated.