Setup seperate sites targetting each visitor group. Use geotargetting to redirect the visitors to the correct place (e.g. if a USA visitor ends up on your Canada store, you want to give them a notice link to the correct store)
Nice to see that you finally made a sale. What I would advice you do is start writing article on your blog and inserting Amazon links in there. That's the way that most people use - and it works. Relying on banners and other forms of advertising does not convert very well. So, have a think about product reviews with embedded links. Good luck!