I got them through a firm called, Tour-beijing.com
They charged a fee of roughly $12 per ticket and I also used them for a one day tour in Beijing.
I know that I could have gotten them myself at the station, but after seeing the madhouse at the station, I am glad that I did not go there 4 days before the trip and try to find tickets.
They delivered them to the hotel as promised, and peace of mind is always worth something