if you hired a coder one day that had access to your site, too late, the coder stole your stuff and sold it to another guy...

I do believe you've been hacked.

I have never given any coder access to this site.

I did receive a reply from the admin of the forum where my stolen content appears, he said he purchased the forum when the content was already there, so he doesn't know how it happened.

What recourse do I have here?

Probably someone ripped your Database and now he is using it.

--------------- Added [DATE]1290376435[/DATE] at [TIME]1290376435[/TIME] ---------------

Details of the purchase, From where he did whose the guy email etc.

To be honest,

Evaluate your security.
See if he is willing to accept your terms whatever they may be.
The whole contacting of authorities just doesn't seem to get you anywhere from my experience.

sounds like an inside job.

someone that works at your host Id guess if you didnt ever give anyone access to your server to work on it to install anything for you.