Everyone knows (or should know) that the BEST way to keep a scammed account is to buy a new account of the same last name, transfer the character over to it, and get the old account banned...
But paying by credit card and your own paypal is risky at best. Thus, you should find out exactly how much WoW and TBC keys cost (lots of sites do online delivery and they are cheaper than buying boxed games). Next, go buy VISA or MASTERCARD Gift Cards. They can be bought at most groceries stores or places like Walgreens or RITEAID and they look and function like any debit/credit card, but they are completely anonymous. Use these for purchasing your CD keys and transfer.
For even more security, purchase 2 different gift cards and use one for the transfer and the other for the CD keys.
And, if you're REALLY paranoid, you can purchase the gift cards with cash. If you do this, there's no possible way of tracing either of these payments back to you... ever.