not sure if its the entire song, my friend showed me and it sounds about right so.

the Chords are G, Am, F, C

Sorry I know I'm not much help, but I really like this song and was disappointed when it 
here. And as for the strumming, I suggest a video on You Tube, I found it to be quite helpful.

http://www.youtube.com/watch?v=HaiKl62lt34

Good luck.