At the moment, your intro div has a fixed width, so repeating the image wouldn't change the current appearance (much). The image isn't quite ready for repeating yes, as the ends don't match up, but perhaps that could be changed. If you want the image to repeat across the screen, you'll need to perhaps put it on the <header> instead (which shouldn't really have the intro part in it, I'd say, but that's another issue).
We'd need to know a bit more about how you want this to look. If you are going to repeat the image across the screen, you'll want to detach the bit at the bottom of it, I'd think.