After a forum database issue destroying data at the official Ubisoft forums, word comes down that Tuesday (check your time zone, Tuesday is a vague notion depending on where you live) update has two parts.

The free portion is a new weapons pack for SP, while the new paid content will also be released. Speculation on the cost for the new map/mission pack is rampant, due to apparent inconsistencies between Ubisoft and Microsoft, but it should be available on the Live Marketplace in less than 24 hours from this time of posting.