Integrating WordPress with another site

I’ll probably be lambasted for this but…

you’d probably be better off by just adding in a comment form to what you’ve already got…

you might run into spam issues though, but I don’t see a real easy way to bridge the two.

you might try looking at
http://www.zimmertech.com/tutorials/php/25/comment-form-script-tutorial.php
and
http://www.gentlesource.com/comment-script/