In Angels its the first time Amy meets River. When the Doctor introduces Amy to River, River kinda ignores it all and gets on with the job, so I'd say River has met Amy many times before. Plus if they're meeting at opposite ends of their time scales (assuming Amy's is the same as the doctors) then Amy's first meeting would be Rivers last possibly, or somewhere in between if they're completely out of sequence!
Also I rewatched the Angels episode today. I definitely think River will be the Doctors wife:
Amy - you're so his wife
River - this is the Doctor, do you really think anything could be so simple
Amy - yes
River - oh you're good, i'm not saying you're right, but you're good!
I recon Amy was right!
The Bishop in same episode tells the Doctor not to trust River, when asked why, he refuses to say. All he says is the reason River is in prison cos she killed a good man, a hero to many. Doctor confronts River about who she killed, she just says a good man, the best there ever was.
The Bishop also keeps threatening River with telling the doctor who she is, he says she's the only one who can manage the Doctor but that only works while he doesn't know she is - why? unless she is his killer. The only reason i can think why the Bishop doesn't tell the Doctor who River killed (other than timey-wimeyness) would be that he needs the Doctor to keep listening to River during the episode!!
Wish I knew Moffat then i could ask him!!!