Questions About the Recruit-a-Friend Info

Please don't delete this, not complaining at all but I do have a few questions about how this all is going to work.

I play with my girlfriend, we level exclusively together, raid together (when in raid guilds), etc. The ability to have 90 days to level up 2 new characters at 300% is too good to pass up, especially with the other neat bonuses included, even if that means creating a new account to do so. Is this really the best option for us? For 50 dollars we could get the vanilla WoW and BC, and get the mount as well as 90 days of super fast leveling. We'd also be able to spread 30 levels or so around her alts, which would save us even more time having to level toons before WotLK.

I just don't want to end up purchasing a new account and everything, and then realizing this is going to also be offered to two people with existing accounts in some sort of other fee based service. To be honest it does seem kind of strange this can only be achieved in the way announced so far.

I'm hoping a blue could answer if, for my situation, it really is best to just go ahead and start a new account.