Did you apply for your work permit already? If no then see point 1 and 2 but if you did already then you can only wait and pray that you get it approve before your internship starts.
1. You should make paper application because processing time for paper applications is better than online these days.
2. If it is possible and you can go to the nearest border and get your co-op work permit right away. But make sure, you meet all the conditions and have all required document before you go for this option.
1. Valid study permit 2. Valid Passport 3. Single entry(if only visit US) or Multiple with valid TRV unless you are TRV exempt. 4. Co-op letter from your institute
Check these links below for more details about co-op WP and getting a WP at a border.
http://www.cic.gc.ca/english/study/work-coop.asp
http://www.canadavisa.com/canada-immigration-discussion-board/flag-pollingpost-graduate-work-permit-for-international-students-in-15-mins-t355050.0.html
FYI: One of my friends applied online on May 17th and got his work permit approved on September 22nd. I also know one person who applied online in June and got his WP (co-op) approved in August (he was just lucky because CIC processed June applications first than May).