Here's the latest info from Michael Hurst's Official site. Michael has directed episodes of Spartacus in previous seasons and now in War of the Damned which is the final season of the show.
Late May-June 2012: Spartacus: War of the Damned
Michael directed episode 3.4 and will direct episode ep. 3.9 later in the year. It will premiere on Starz in the U.S. in late January 2013.
For more Spartacus War of the Damned News check out the AUSXIP Spartacus War of the Damned page