Hey there,
So the community involvement comment was a slight assumption on my part given what you'd written. Your involvement with New York Cares is notable and BBBS is a great organization. What it will come down to is your impact and scope. If you're a mentor, that's fantastic. But if you are on the junior board or help them with strategic concerns or something along those lines, then that's a very different type of involvement. Volunteering is great, impact is better, and scope takes the cake. Does that make sense? If you want me to clarify, happy to do so.
As for the pre-MBA coursework. Make sure you bifurcate between what you need to do to shore up your quant skills for your application and what you need to do to be successful when you get boots on the ground. Most pre-MBA coursework is completed by folks who are already in but are worried they might need a refresher / intro on some of the concepts MBA programs require you to know. Also, some of those pre-MBA programs don't offer grades and may not be from accredited institutions. However, Berkeley and UCLA are the two relative heavy weights in this space. Here's a good option from Berkeley -
[Math for Mgmt] and you can find out more about UCLA extension
[here].
You're being proactive which is great so keep that up and make sure you do a little research so that you not only pick the best option for your apps, but for you too!
Bhavik