You could have a selector, or just interpret the price based on whether they came to the .ca version of the site or the .com version (perhaps have a link back and forth). Then add the price options in the table and do the associated pricing.
I think we could do it in about 2 hours. Just get both domains pointing to the same IP and same set of files and then set up the first hour. We can get as far as we can and see if there is anything you can do on your own, then do the second hour to clean up any leftover issues.