From what I understand, an ADN graduate would only qualify for an RPN license in Canada. To be an RN, you would need to completed a bridging program to get a BSN and most of these take roughly 2 years. I know that York University has one for internationally educated nurses.
Hope this helps!
Kim
College of Nurses of Ontario:
http://www.cno.org/international_en/index.html
York University Nursing
http://www.atkinson.yorku.ca/NURS/