lammert - 4:23 pm on Sep 16, 2010 (gmt 0)
Sorry to hear that your website has been hacked.
One possibility is that the other website is not actualy copying your website, but that they frame your content in their domain name with either normal frames or iframes. It may be worth investigating that first.
If you run Internet Explorer you can check if the mirror site is using frames by going to that site and clicking with the right mouse button in the content. If you select the "Properties" option in the menu, you will see the actual path of the content. If this path is to your domain, then the mirror site uses frames. If the displayed path contains the mirror site domain name, they have copied the contents of your site to their server, or use their server as a proxy server to your domain.