HI There,
Here is a link to the Interior Design Association of Canada.
It in turn has sublinks to provincial associations. The Ontario site has hints on how to find the right designer.
The site also has sublinks to the websites of the design firms.
You could contact a few people and see who you like.
There is also your local yellow pages, paint stores and fabric stores.
However, before contacting anyone, you may want to get your ducks in a row. That is, develop a binder with photo inspirations, preferred colours and finished, and a written list of all of your requirements, priorities and expectations including timelines and budget.
http://www.interiordesigncanada.org/link_assoc.html
Good luck, Evalina