Indeed, I am a bit confused. The T1 does not support the old Reader Library software (or, rather, is not supported by the software). So you need to download the new Reader for PC. One you install it, it should prompt asking whether you wish to auto-import your old books and collections.
The download link:
http://ebookstore.sony.com/download/
Yet, beware. While the old software is not compatible with the T1, the new one isn't compatible with anything. Well, just kidding. It's supposed to work with the T1... and it somehow does. But it's full of bugs, it freezes, it doesn't display notes correctly, it is clunky, it won't let you delete some content... fun stuff...