From the Tor.com e-newsletter:
"The BBC and Radio Times have released the title and episode poster for the final episode of the current season of Doctor Who, scheduled to air on May 18th. ... “The Name of the Doctor” will feature the return of Alex Kingston as River Song, last seen in “The Angels Take Manhattan.”"
I love River Song and look forward to that episode. Lots of interesting speculation in the Comments. Link: http://www.tor.com/blogs/2013/04/doctor-who-season-finale-title-revealed-river-song-to-return?utm_source=newsletter