Sorry, how would this have any effect on River? The Ponds are zapped back in time, meet and adopt the newly regenerated Melody as a toddler, and raise her in Leadworth. She grows up as Mels, not realising her adoptive parents are also her best friends at school. She then meets the Doctor as seen in 'Let's Kill Hitler', regenerates into the Alex Kingston version, and gives up her remaining lives to save the Doctor. Her life then progresses as we have already seen. As I say though this is all speculation. Another twenty four hours and we will know.
So, the Ponds leave Dr Who tonight - will it be "heartbreaking" and "need hankies"? I doubt it, really. Maybe just because I have a sort of opposite reaction to hype - tell me what I will be feeling and you guarantee I won't... Or maybe it's because they already had such a perfect leaving episode last year that it'll be a relief to move on...
I'd like to change my answer to this question now. If I edit my original post, however, the entire TrekBBS will be ripped apart so I guess I'll just leave that one there.