Looks like we won't have to wait too long for the Prometheus sequel; rumored to be titled "Paradise". The HollyWoodReporter recently caught up with Fox who said the following:
The studio's big summer bet was Ridley Scott's Prometheus, June's sort-of Alien prequel. The $130 million-budgeted film grossed a solid but not spectacular $303 million globally, putting it right on the franchise bubble. Fox confirms to THR that Scott and the studio actively are pushing ahead with a follow-up (stars Michael Fassbender and Noomi Rapace are signed) and are talking to new writers because Prometheus co-scribe Damon Lindelof might not be available. "Ridley is incredibly excited about the movie, but we have to get it right. We can't rush it," says Fox president of production Emma Watts, who also has overseen the successful reboots of the X-Men and Planet of the Apes franchises by turning over the reigns to innovative filmmakers. A Prometheus sequel would be released in 2014 or 2015.