Actually, the ability to tranport inter-planetary distances was shown to be possible in the original Trek Series, in the episode "Assignment Earth",
SPOCK: The beam is originating at least one thousand light years away.
SCOTT: No transporter beam can reach that far, not even in our century. (Kirk enters.)
KIRK: Something is shaking us apart.
SCOTT: It's locked, it's locked our circuits wide open.
(One of the transporter pads has activated.)
KIRK: You're right. Something is beaming aboard.
Given that Khan transports from Earth to Klingon in the rebooted Trek film, and that the Klingon border is described in Star Trek VI: The Undiscovered Country as being "a thousand light years away from Earth", this also the answer to your question.
1000 Light years is the farthest we see anyone transport, however there's no evidence that this is the upper range.