US Airways Booked my travel for the wrong day, admitted to the error, and I have to pay more Internet

I booked a business class round-trip from Philadelphia to Shanghai.  US Airways booked me for a return a month later than I asked for.  I received confirmation of this two days after making the reservation on the phone with their agent. 

When I called back, to fix their error, I was told flights were sold out the day I wanted to return and would have to come home the next day.

I would also have to fly an additonal 8 hours, fly in coach on the US Airways portion of my flight, but they were still going to charge be the full business class price.

In addition, it was my responsibility to pay for the hotel, meals and additional airport transportation fees.  They were responsible for nothing.