Post graduate work permit is part of the study permit package for most international students. The process of applying and renewing this type of work permit is independent to HRSDC. As far as I know, for renewing work permit, you can only mail the application to Alberta immigration office and the process time usually is one month.
From my experience, I think most soon-graduates should focus on looking for job, all kinds of jobs, sales, call center, technician, administration.... As long as you get work permit, within two year, you can change job, renew work permit, apply for immigration, wait for immigration...whatever you want to do.
Don't give up, try every possible way to get a job offer!