OK here's a couple to try. The full screen one will fill the screen, but I had to blow it up to you screen's resolution, and thus there's some loss of quality. Might not be too bad at phone size though...
The other option is to do it like the second one - keep it the original size and add some background filler (the background can be easily changed if you want.)
Hopefully, one of these will suit your needs.
Previews only - do not save!
To save them in full 720x1280 resolution - Follow the link(s) bellow and long press the image on your phone until the save option pops up, Then find it in your photo gallery and set as wallpaper. If it looks fuzzy, you may be better off viewing it from a computer, right click and "save as", and finally transferring to you phone via USB or email.
Links to full sized versions ↓
BidCix-n-Son_720x1280.jpg
BidCix-n-Son_2_720x1280.jpg
One other option would be to use a third party app to set the wallpaper. The two I see most commonly recommended are "Wallpaper Wizradrii" and "Wallpaper Set and Save".
Best of luck, and let me know if I can be of further assistance -
eyebeam
Edit: Great shot by the way!