#2 - Aug. 23, 2010, 8:03 p.m.
The first and most important part of any compromise is finding the source and making sure it doesn't happen again. Trust me, if the source still exists and they CAN get back in, they WILL be back.
This is in process for a restoration investigation - but it's imperative you find out how they came by your password and ID.
You need to make sure both your system and your email account are secure.
This sticky may be useful.
Account Hacked? Security Issue? Look Here!
http://forums.worldofwarcraft.com/thread.html?topicId=24702231244 You may also want to look into getting an authenticator for your account. It's no substitute for good security habits, but it will help keep them out of your WoW account.
Blizzard Store
http://us.blizzard.com/store/browse.xml?f=c:6 Mobile Authenticator
http://us.blizzard.com/support/article.xml?locale=en_US&articleId=26109