Can we delay relocating to Canada?

Hi

I believe we have to complete 2 years stay in Canada after receiving the landing papers. We have been unable to do so...

My husband has been in the US completing his phD and we havent been able to relocate in canada as per the requirements.
I received my landing papers in Nov 2001 and my PR card a couple of years later. The last time I visited Canada...some 4 months ago,
I was told that my window to relocate initiating from 01 had already expired (I was misguided into believing it started from once you receive your PR card.)
However, they reconsidered the situation with my husband and asked me to move to Canada by November of 2006 or lose my immigration.
My husband, however, does not complete his studies till some time next year which puts us in a bad spot.
My question is, is there are a way to apply for extension in such circumstances and if there is,
what is the likelihood of the application being accepted? We really dont want to miss this opportunity.

thanks for your help folks.

regards