I love this song - I heard it on Grey's Anatomy a few months ago and needed to have it immediately! I finally found out that it is Katie Herzig's "Lost and Found" from her album "The Waking Sleep" that came out in September 2011. Grab the song on iTunes here:
I've been using it in my jazz & contemporary warm-ups and cool downs. The beginning starts off slowly, but make sure you listen through until about 2:10 when the chorus starts in and the song really starts to take off... it has such an uplifting feeling! My teens really enjoyed this song and the lyrics are PG enough to use for younger students as well.