WoW account hacked, but haven't logged on in weeks

[Maelstrom]

(I realize this isn't the WoW forums, but I was hoping since this is a tech site my question could be answered =D)
My WoW account was hacked yesterday, but what is odd is that I haven't logged on in weeks (only logged on on wow website to cancel sub), and the last time I played was over a month ago. Furthermore, the comp I played WoW on I parted, and I am using a laptop as of now. Now, I have avira antivir personal and malwarebytes installed on my laptop. I ran both of those and they found nothing, and none of my other accounts (banking, email, Aion, etc) have been compromised, it appears.

My question is how . Did they get the info awhile ago and just wait? Or is it something else? I'm kinda freaked out tbh, as I'm worried about my other pws and such .