If you install the Adobe DNG convertor, can you then edit D600 Raw files from within Photoshop? If not, that really sucks. I used Photoshop CS3 for years. I recently upgraded to Photoshop CS6 Extended to take advantage of my new 64 bit Windows system.
BTW I never develop Nikon Raw files in Photoshop. I use Nikon Capture NX2 and then make any final adjustment with Photoshop.