Normally they will not mail you a renewal PR card, you have to go and pick it up at the immigration office closest to where you live.
Since there is probably no Canadian immigration office close to where you live right now, you should call immigration and ask them what you can do. If you let your PR card expire, you might have problems when you try to enter Canada again. I am sure when you explain your situation to them that they will offer you some kind of solution. When they do, of course I trust that you post here what it is so we can all know for our future references