Renewing China Resident Visa

Hi, my wife and I are Canadian who successfully obtained China Work Permits and China Resident Visas almost a year ago. We initially applied only for 1 year. Expiry is coming due end of January 2012. Can you kindly outline the renewal process? Also, for myself only, my Canadian passport that has the China Resident Visa has expired. I'm currently going in/out the border with both my old passport (with China Visa) and my new passport to gain entry. Thanks for your help! I really appreciate it.