To maple,
Actually and specially in your case, i would advise that you contact Buffalo visa office as soon as possible because of many reasons; the expiry date of your medicals along with the expiry date of your temporary status in canada. if you reach the expiry date, you will have to leave canada without any excuses. so the whole process of your application will go back one year or even more between informing them, change of address change of visa office(transfering your file), retaking the medicals...and so on, or even closing your file justifying that they were sending you a letters on your address in canada without any respond (you are already in canada and hardly able to contact them, how about communicating with them from overseas !!!!! sometimes you know how smart they are).
My opinion, GO for it man and inquire about your case (which is in the very last step), you have nothing to lose at this critical time, but if you leave canada without having any information you will suffer to be able to contact the dead office (Buffalo) with the smartest immigration officers around the world who remember to ask the applicant to send documents related to the work experience after recieving his medicals and the RPRF !