Hello Iris, welcome to MobileRead.
I also live in Canada and have also noticed the increasing number of "US Only" ebooks at Sony's Reader Store. These geo-restrictions are affecting us all. You have to search around the various eBook sellers to find out which will sell to Canada. You often have to pay a premium to get an ebook you want because it isn't available at the Reader Store.
There are some price comparison sites that I use to help me find ebooks, in the
EPUB format, which can be read on our readers:
Inkmesh
AddAll Ebooks
eBook Price Info
There is also a list of ebook sellers in the
MobileRead Wiki under
E-book stores.
I buy a lot of my sci-fi books from
Baen Webscriptions because they are DRM-free. I've also found that
Kobo and
Direct eBooks sometimes have titles I'm searching for and are available in Canada but, like I said, usually at a premium.
I hope this helps.