Common Law application and OWP

Hi there,

A little background first:

I was working in Canada for 2 years on a temporary work visa up until November 2010. I had been living with my Canadian girlfriend from May 2010, but returned to the UK in November for 9 weeks due to the expiry of my work visa and a family illness. I returned to Canada in January on a tourist visa and am just about to make an application as a conjugal/or common law partner. I say conjugal/common law, as I was out of Canada for 9 weeks, which I understand discounts me from applying as a common law. I understand the conjugal route is to be avoided.
It's now going to be difficult to apply as common law as I'm here on a tourist visa and that expires in July, so it's going to be difficult to be together for 12 months in one stretch.

Does anyone have any advice as to what my options are? What is an open work permit and can that be of any use to me being as I'm currently in Canada?

Any advice is appreciated.

Adam