My email address is in my profile if you want to get in touch with more questions :)
After some further research, it does seem like Interactive Brokers is a good option for the OP. For posterity, here are two blog posts by a Canadian describing how he uses Interactive Brokers: http://blog.plsoucy.com/2012/11/best-way-to-convert-usd-to-c... and http://blog.plsoucy.com/2013/03/converting-usd-cad-interacti...