transit visa for U.S. passport holders

My partner and I have an 11 hour layover in Beijing, and are interested in going out of the airport. From what I've read on your site, it seems that we will have to apply for a transit G. Is that correct?
Where do we turn in the application, how much does it cost, and where could I access it in order to fill it out and print it?
Thanks for all of your help.