Here is a little snippet sent in to me which gives us a timeline for an exciting end the year, first of 2013 codex release for 40k. Accordingly Dark Angels will probably be released for pre-order before December is done, and up hitting the shelves January 5th.

That would be a great way to start off the new year.

via the Faeit 212 inbox (anonmyous as I have no permission to use the sources name)
the next WD is hobbit releases and the WD after will feature Dark Angels.
DA codex will be after Christmas though.