Hi, there!
First of all @myrmidonqueen Congratulations on your admission to UOttawa! I am currently a prospective student and am waiting for a response from McGill and UOttawa respectively. I have been looking at the Ottawa housing market, and I would recommend waiting it out to find housing, the places being posted right now aren't the best. A friend of mine found her flat in July and moved in on September 1 so do not despair! I would recommend if you are sick of Kijiji and the billboard investigate WalkScore and PadMapper. Both are stellar in weeding out the frauds and are centralised systems that take into account all of the housing websites and their postings that are available!
Did you ever hear back from McGill? And, if you don't mind my asking what was your GPA and proposed area of research. If I am not accepted at McGill, I hope to see you and others in Ottawa!
Here are the links to PadMapper Ottawa and WalkScore Ottawa
https://www.padmapper.com/apartments/ottawa-on
https://www.walkscore.com/apartments/search/CA-ON/Ottawa