I don't think there would be a new song, because of 2 factors:
They JUST released a new album
Castle of Glass and Lies Greed Misery are both in the soundtrack, and the newer trailer features COG
Maybe a new game or possibly a tour could be announced, the next chance we probably have at a new song is probably either going to be a new album (because they said they were going to release an album every 18 months), or the next Transformers movie, which comes out in 2014.