I do not have any inputs regarding colleges specific to Canada. I believe GMAT is essential.
But one thing i'd recommend, is that since you run your own company, a 'standard' MBA is not that useful. Look carefully at any course and its subjects, that help any businessperson run his business, and most importantly, helps build a network that will be useful for the growth of your business.
For example, If I were running my own business, the 'Global' MBA I did at SPJCM (currently SPJGSM), would have been almost completely useless.