Thanks for all the advice, everyone. There is no way to contact the person who plagiarized my material other than by mailing the owner of the domain name - the email address for the site isn't active and there's no contact information. I tried posting comments asking for attribution and got no response. So I've filed a complaint with the server to try and get the material removed.
Meanwhile, agent says there's one little contract detail to work out and hopefully I'll have happier news tomorrow.
And thanks for suggesting Medievalist, Calla, she was terrific!