When will Escalation come out for black ops on the ps3?

So yesterday, i was on my account and did a trophy compare with a friend. That's when i saw that there were 3 or 4 new trophies up on the Black Ops trophy guide. All of them containing something to do with the new zombie map, Call of the Dead. So me being an eager beaver ^_^ went to go look for it in the store. Sadly, there was only first strike that was availible to buy. Anyways, anyone have any idea when Escalation will be able to buy?