Chances of you getting a visa to join her depends on if immigration considers you a risk of overstay.
It is possible that she can get PR. If she applies for an off campus work permit after 6 months of studies, uses her last months of studies to find a job and starts working in a skilled position as soon as she graduates, at the same time applying for her post-grad work permit, she should be able to manage 1 year of skilled work which would allow her to apply for PR under Canadian experience class. It is also possible that she might qualify under provincial nominee in her province after graduating and having a full time job offer but that is something she would have to look into.
