Hey Brad. Gee your English accent is fading fast. You almost sound Australian!
Mate seriously there lurks a real good singing voice there. You should definitely pursue that. With the playing, I tend to agree with a couple of points Stuart made. It's kind of a progression. You need to be able to play the tune really well before you should worry about the singing in my opinion. The strumming for mine is a bit heavy, I think you mentioned that yourself. You need more work on the barres obviously and that affects the flow of the song particularly when singing. In terms of where the chord changes lie, go to
www.chordie.com and find the song with chords (rather than tab) and you will probably find a version with the chords and lyrics showing you where to change. In terms of the fills etc, well perhaps Neil will post a response with some suggestions for fills and the intro/outro.
All that said, good job mate, I liked your effort and liked the fact that you explained the problems you are having. It's a good idea.