I would think for the hassle of trying to locate the books in Canada it would just be easier to pick them up in Disney. They cost ~9.00 and have Disney designs on them. I have several from my previous trips.
As a side note, you might want to be sure that your kids are excited about getting them, once you are in the parks. You may spend the $$ to get the book, and your darling's do not show an interest once they are in the parks.
If you want/need a map of the locations google "pressed pennies disney locations" you will get a number of links. There is also a great thread on pressed coins here on this forum.