60day pre-paid game card cannot be redeemed

HI, I'm very new to the game (just started yesterday). My friend recruited me and got me a 10 day free trial from the recruitment. I'm now wanting to fully upgrade my account and I went down to Gamestop to buy a 60 Day Pre-Paid Game Card. I got it with no troubles, brought it home. And am now having trouble upgrading with it. When I go to the upgrade page at- https://www.worldofwarcraft.com/account/index-trial.html it gives me 3 options, a direct online upgrade, a CD key from a retail copy, or order a box copy online. I thought the closest way to it would be the CD key but the number line setup is all wrong, I simply cannot type in the card because there is too much room in some number combinations and too little in others. I then found this link- http://www.worldofwarcraft.com/gamecard/?rhtml=y which basically told me go to the first link I put up here and choose option Game Card, only problem is there is no option as described, there is only the 3 I previously mentioned. I also have no credit card so the game card is my only option. If anyone could please help a link is all I need, I love the game and really hope to play more. Thank you for your time.