Someone or something must have been watching amy for a very long time because how would kovarian know that she was travelling with the doctor, that she had a wedding and that her and rory had sexy time aboard the tardis in mid flight, which had to of happened for all this to of happened. The doctor also knew the possibility of this hence him insisting on bunkbeds :L

They bugged his Tardis?

Surely would of been detected though, right? I suppose the same could be said id something was on board though, hmmmm

Maybe she knows the Silence - they could have been on the TARDIS for millennia without any detection spying and gathering information. We still don't know who, if anyone, they are connected to.

I just assumed she was from the future,and thats why she knows about Amy's superbaby,and also why the Doctor doesn't know her or why she is his enemy yet?

the silents .

I'd guess they were watching her before this season began

Well, you meet up with The Doctor, pretend to be a nice normal person and engage him in conversation and then find out what you need to know about Amy et al.

Then you jump in your time machine and go wreak havoc with the past and bend it to your will / desire.

Mrs K wouldn't doesn't need to know how River got to be whatever she is. She'd only need to know that she is "special" and her date of birth.