#5 - March 3, 2010, 7:44 a.m.
Q u o t e:
what softwares can I run for free that can help me detect these malwares and keyloggers
This Sticky FAQ has quite a few - and helpful information.
Computer Security Recommendations
http://forums.worldofwarcraft.com/thread.html?topicId=1778038509&sid=1 As has already been mentioned, if they can continue to obtain your information - they WILL be back.
If they are so readily accessing it - that makes me wonder if your email might also be compromised. It's entirely possible they are pulling information directly from there.
I'd also recommend changing that password at the very least once you are certain your system is secure.
I'd also highly recommend looking into an authenticator for your account if you haven't already done so.
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