1- Since you are only accepted to one school, there is only one choice. Toronto is considered to be very good in CS (I would assume you were accepted into Sciences, and are looking for a 2nd year admit into CS?). Expect to be worked very hard there. I am assuming that you are fine with a very large school in the middle of a very large, though mostly benign, city?
We need a lot more info from you before we can advise, ie. what is your nationality, what are your expectations from a school and city, what is your budget.