Having a green card gives you no advantages when applying for PR status in Canada. You still have to go through the same application process as anyone else. Canada's immigration programs are listed in the link below and you will have to read about them in detail to determine which you might qualify to apply under (I would suggest you start by reading about the Skilled Worker under Express Entry program):
http://www.cic.gc.ca/english/immigrate/apply.asp
Having a formal job offer in Canada for a permanent job will likely help you to get PR status. However in order for it to be classified as a formal job offer, having a job offer isn't enough - your employer must also obtain an approved LMIA. If your employer doesn't have an approved LMIA yet, they should start this process now since it takes several months to complete and not everyone is successful in getting one. Also, the job offer must be permanent and not temporary.
