Perhaps, before I offer some suggestions to help you along during your visit to Canada, you would consider rethinking the term "hour building". How about "building experience", or "broadening horizons". "Hour building" brings to mind a pilot who has an hour a thousand times, rather than a thousand hours - there's a vast difference! While you build experience, the hours will come your way too! As you are venturing this way, you are obviously, you're obviously broadening your horizons, so let's make the best of that!
In Ottawa, you will find the Rockcliff flying club (they apparently have a Citabria which will fly backwards):
Learn to Fly in Ottawa - Rockcliffe Flying Club
though I do not know if they rent aircraft, you'd have to contact them. Also, the Ottawa flying club, at the international airport, who rent.
Ottawa Flying Club | Stop Dreaming - Start Flying!
Less than an hour up the highway, in Arnprior, you can contact:
Chapman Aviation - News
More in my direction, and a 4 hour drive from Ottawa (and an hour and a half from Toronto) you'll find Lake Country Airways.
Lake Country Airways: floatplane training, endorsements, float charters and rentals
The great thing about this company is that they rent 172's on wheels and floats. You can do some experience building on wheels, and get a float rating too. A float rating will certainly add to your wheel flying skills.
Nearer to Toronto is Brampton flying club. They rent out a 172RG:
Brampton Flight Centre
Keep your expectations low, I very much doubt that you'll find an Arrow/Saratoga/C182 for rent. Plan on finding a 172, there are lots of them around.
If you need more detailed information, let me know, I have contacts....