Someone may know more than I but I doubt if there is a readable file containg passwords as it would be insecure if stolen. You may wish to download a password keeper (I used KeePass for a while which was ok) and then you'd only need to remember one password to get to all the others.
Maybe if you stated which web browser you used before IE9 someone may know how to transfer the passwords across ? Were it a previous version of IE I'd have thought they'd have transferred with the install, but I guess not.