"The River who tells him off is younger than the River who tells Ten that he's not finished and talks about how awesome HER Doctor is, so she's done a pretty big U-turn by the time she gets to the Library."

Yes, exactly. As far as we know River meets the Doctor in the library for the last time (and he meets her for the first time). So at this point, River should know ALL about their story because her story ends there. So it makes no sense for me that she gives him the whole armies-turn-and run-speech in the library, when she should know that exactly this kind of behaviour will be his downfall and she tells him off for it at an earlier point in her timeline. Jeez, this gives me a headache...