there is so far no film "River Flows in You" by Yiruma soundtrack.
This piece of music was very widely used in fan videos to the "Twilight Saga" and became famous. Maybe you know it from such a video, or have it on the radio (was in the charts)?
The band "Eisblume" has the melody of the song "Forever" uses, perhaps you've heard the time.
A piano piece from "Breaking Dawn" is "Bella's Lullaby" by Carter Burwell.
Best regards :)