This is not possible. MobileMe went over a year ago now and there was only a limited time for anyone to recover sites and host them elsewhere. As you have left it this long, it is not possible for you to recover anything from MobileMe at all and as Roger has pointed out, it would not help you, as iWeb has no import facility, so you would be looking at re-creating your site anyway.
You have not been charged any fees at all for any hosting since MobileMe went and this has been over a year now.
If you created your site in iWeb then you'll need to find your domain.sites file which is the data file where iWeb stores everything that you need. This is found in your User/Library/Application Support/iWeb/domain.sites. Double click on this file and iWeb will open it. If you don't have this file, then you are looking at re-building your site from scratch.
You also need to find alternative hosting and upload your site to this new host if you want to continue to have your site.