if you want to apply for canadian PR, apply after coming here.  it is definitely good idea to come here and pay your debt.  it would be very difficult otherwise unless you are very rich.  i think you should come in spring, pay your bill and work your ass off and try for both assistantship starting summer and job.  did you apply any canadian universities?  like i mentioned before, it is not only about getting job, it is about finding a company who is willing to sponsor your visa and wait you until october.  remember, you dont have OPT, so you can not work even though you get a job without H1B.