According to this post by ktsummer, the next single is a song called "Single" (featuring Ne-Yo), so it looks like it is not "Dirty Dancing".
They performed "Summertime", "Tonight", and "Click Click Click". And they played "Full Service", "Big Boy/Big Girl", and "Single" off of their new album.
Click here for some photos and short videos she got from the event
Anyone else go to this event? Let us know the details!