I support everything that chrisridd said (above). We don't have a Sony store in New Zealand either; Sony even forces us to register our country as Australia if we want to use their software. Sony apparently doesn't know that we exist as a separate and sovereign country.
In short, I use my PC to buy ebooks - if I am buying from Amazon, I use Kindle for PC. I then transfer the books to my PRS-T1 using Calibre. Sony Reader is very poor software, so I have uninstalled it. You don't need to use it - Calibre is much better, especially if you have all of the plugins installed to assist you with the different ebook formats.