Hi Jay - that is very unfortunate news. Sorry to hear about your account being hacked.
As a site Administrator I'm not going to say it's impossible that your forum password was uncovered somehow but I find it very very very very very unlikely that this is the case. As an Administrator, even I can't see your password. I can reset it, but not see it.
As for some hacking tool that might do this, I guess they are out there but TOG has been playing WoW for a long long time (3+ years) and I can't say we've heard many (if any) stories like your own.
I think it is merely co-incidence that your account got hacked immediately after signing up here. Of course if you have a good reason to suspect foul play the Administrators would be very keen to hear more from you.
I don't know if you've resolved the issue with your hacked account but perhaps you can still trust us and post your story in the TOG WoW forum. You may find some very helpful advice on ways to restore your WoW account.
I don't know if this response helps you but I do hope you can resolve your WoW issue and continue to enjoy the great TOG community.