Hah, not helpful but I literally live/work like 5 minutes from there.
Try Craigslist: http://toronto.en.craigslist.ca/apa/
Or Kajiji: http://toronto.kijiji.ca/f-real-estate-room-rental-roommates-W0QQCatIdZ36
If you're looking for an apartment you could always walk around the area and look for places with signs up that have rooms to rent. There are a decent amount of apartment buildings on Sheppard Ave.
I see. Well using those two websites I gave you, look for places in Agincourt, or Scarborough, and then look on a map to see how close they are. The location of your internship is in Scarborough, but the nearby 'neighborhood' is called Agincourt. Anything in Agincourt will be very close to that location. Hope that helps.