Great self-analysis there! Your clear understanding of the strong and weak areas of your profile as an applicant will be an asset in creating your applications, and attractive to top business schools as well.

It looks like you're aiming to applying in fall 2018, which would give you time to further strengthen a few areas. Yes, you want to crush the GMAT, but get that out of the way ASAP. In parallel, I'd want to see you crank up your community involvement in a leadership capacity, so that you can knock out both of those issues at once. Leadership, i.e. team leadership, is an important part of your holistic application profile, but it looks like you have enough experience so that you could tap into a past involvement and start sharing the professional perspective you've worked so hard to earn.

Coursework: that can be kind of draining, so you might want to take a practice GMAT to get a baseline number, see where you fall in the Quant/Verbal spectrum, and then add any coursework you might need that would be targeted both to increasing your GMAT (it does help) and also preparing for what you'll need to be doing in b-school.

At Stacy Blackman Consulting, we offer a "plan ahead" package that might be ideal for you. You can check it out here: https://www.stacyblackman.com/plan-ahead/
Making the most of the year before you apply is crucial for you as an applicant.

Good luck!
Margaret Strother