Why not just go through the renewal process right now? you'll get your passport back in 2 weeks. I just did mine, and it came in the mail quite fast. Even though your passport is expired, I believe you get some slack on the time required to renew it.
Fill out the renewal form, get your pictures, and you're good to go!
http://www.ppt.gc.ca/info/ren.aspx?lang=eng