Dear Deb,
I do not think you should retake your GMAT at this point and instead focus your efforts on your applications. 710 is a great score and you appear to have some strong work experience. What makes the difference for any applicant is how well you put your application together. It is imperative you present a strong rationale for why you want a MBA, how it fits into your overall career plan, and why the school you are applying to is a good match for you. Likewise, you must distinguish yourself from the competition and demonstrate successful leadership experiences/evidence of leadership potential.
In terms of subsets of the applicant pool, the large majority of schools will view you as Canadian since that is your home country. There are a few that break up the pool on ethnicity, but that is not as common. However, since you grew up in India and have a software background, I would suggest you focus your resume and essay examples on your transferable, managerial skills and not focus on the technical aspects of your job as a way to distinguish your application.
As for extracurriculars, you need to pick the organizations and activities that interest you the most. Doing something because you think it is an activity the school is looking for will not benefit you. Schools do not have preferences on what you do; they simply want to see that you have a life outside of work. Likewise, examples from these activities can be quite interesting in your applications.
I don't see any need for you to take courses or gain certifications. But if you want to gain some exposure to business coursework prior to business school for your own knowledge and development, then taking classes at a community college is fine. As for working with a consultant, you will want to contract with one in the spring/summer prior to submitting your applications.
Good luck,
Lisa