The free, meaning it will cost you nothing if you have the Cerberus Network, Firewalker
DLC will be released on March 23rd. The Cerberus Network will notify you of the new content and you can download it in-game. This piece of DLC includes a new vehicle, the Hammerhead, with five missions focusing on this well oiled machine.
The Premium DLC, that means you will have to pay for it because of that nice achievement, will be available on April 6th. Kasumi’s Stolen Memory
will bring aboard the final ship member Commander Shepard could recruit in Mass Effect 2
The only details about Kasumi’s appearance:
Cerberus has contracted her to assist Commander Shepard in the mission to save mankind
However, like all the other allies, you must help her out before she helps you out. There will be multiple missions (read more than one) where Shepard and company will attempt to recover some “lost” artwork. Bundled with the PDLC is a new Locust Weapon but no details have been released about it.
There are reports out there that the PDLC will cost you 560 MSP but nothing official has come from Bioware’s mouth.
Free DLC: March 23rd.
Premium DLC: April 6th, (reported) 560 MSP, 1 achievement.