I came to Canada on 2002. After getting a certificate in a food industry in a institution in Vancouver, i have been working several restaurant. Two years ago, while moving to a new place to live and also applying for a a new job in a restaurant, my work permit had been expired without my notice. About half year ago, i found out this while renewing my passport.

As i know, i have to leave Canada now and it will be much more difficult if i come back China and re-appy for work permit. However, i want to continuously stay here and work.
Before this incident, my girlfriend( who is Canadian citizen) and i are planning to get married and continue working here.
If anyone know, please help me out with these questions:
1. If my girlfriend and i get married now, can i apply for Spouse or Common-law Partner in Canada?
2. While waiting for application, can i continue to stay here and work legally in Canada or do i have to come back to China to wait for reply?
3. Right now, do i have to do any report to the goverment about my situation so i can continue to stay here?

thank you very much