I had the same situation in Sep 2009. Pretty much fill up extension of work permit application and send it to Vegreville.http://www.cic.gc.ca/english/information/applications/extend-worker.asp
I got mine in two months if I am right since its extension and not a new one. Also call CIC and make sure about the application and the mailing address. I did it a year and a half ago. So please double check it. Best luck.