You can already download the trial version of the release version if you login with your adobe account:

Mac


trials2.stage.adobe.com/AdobeProducts/PHSP/13/osx10/Photoshop_13_LS1.dmg


PC

trials2.stage.adobe.com/AdobeProducts/PHSP/13/win32/Photoshop_13_LS1.7z


... but no Nikon D800 Raw support actually...