Some local shops carry decal paper, just go in and ask. If you can't get it there, there are plenty of websites that sell it. It runs through your computer printer like regular paper, then you spray it with a protective spray (So the colors won't run), and then apply them like regular decals.
If you don't have the other decal to scan, see if you can find a picture from the box, or the internet. If you can't, try your hand and creating the image from scratch in a paint program.
Try a search on making your own decals, I'm sure there are better instructions than I could give.