I remember reading somewhere saying that the sequel will be released around 2014, I guess even Ridley needs a few years to somehow fill in the plot-holes...
Being serious, this was my most hyped movie for 2012 and it just didn't do anything that great. I hated the majority of the characters, these people who're suppose to be really smart act stupid as hell and most of all: the movie itself doesn't even know if it's a prequel to the Alien franchise or not. I literally was waiting for the very, and I mean very last scene to happen for the entire movie, I knew it was coming at some point but that last scene made it a bit better but overall, the movie gave you more questions to think about than it answers for you.
I'm a huge fan of Ridley's work but Promethus overall just wasn't as good as I hoped.