With such a high quant score and very good GMAT, you shouldn't worry so much about your academic record. You certainly could take courses to show your ability to succeed in graduate level education, but I don't think it is necessary.
You should instead focus on rounding out the rest of your application:
What do you do outside of work and do you need to focus on the extra-curricular story?
Have you started on your essays and put enough thought to your professional story?
At this point, I recommend putting together a very strong application on the other fronts.
Feel free to email me if you want to discuss further
[email protected] Good luck!