I had an OK, not great GPA from a consensus top-5 undergrad business program -- 3.1 with multiple semesters on dean's list, but some spottiness due to just generally not liking a number of my professors and having other interests.

Now, I'm taking my career seriously and scored a 720 on the GMAT and am looking at top schools. I was admitted to McCombs for 2010 after applying on a whim, but I'm shooting higher and re-applying to other schools this fall first round.
As far as showing that my 3.1 GPA is NOT representative of my intellectual capacity/ability to do well in MBA classes, what would be the recommended course of action?

One option I'm considering include an executive certificate in leadership program through Notre Dame Mendoza, which consists of online classes graded on an A-F scale.

OR, should I consider taking classes in my areas of "weakness" per my transcript (for example, I had a B- in Intro to Econ, followed by an A in micro and a C in macro, B- in Accounting, B- in stats and C+ in statistical analytics, C+ in coprorate finance, etc.) through other online programs? Would it be advantageous to take online classes from prestigious universities' extension programs (e.g. Harvard Extension), and list on my applications that I'm currently enrolled and grade is pending?