Don't know if this page will open from your location or not, but if it does you can put in a US zipcode and get a list of stores that sell Kobo's in that area. Not all will carry the Aura HD though, if I had to guess most of them don't. It can be a lot of work checking as it doesn't give you a link to the store websites or anything so they have to be individually Googled and checked.
http://www.kobo.com/indie
Here is one store I know some folks here got the Aura HD from back when it first came out. I know nothing about them other than that...
http://www.greenlightbookstore.com/product/kobo-aura-hd