Flying my dog back to the states

Hoping that someone can help me with this one. I arrived here in May with my dog. We flew Continental. Now I would like to bring her back with me to the states in late October. However, I'm getting the runaround (shocker) from Continental here. They are telling me that I have to hire some sort of broker to handle everything (U$D 650). Of course the travel agent knows nothing, everyone is telling me something different. Has anyone ever flown back to the states with their dog? Thanks.
Thanks for the info bjrutledge, however, my dog is 55lbs, and has to fly in cargo. I'm sure that with lots of research I'll be able to figure something out that isn't so costly.