What do you mean by raster art? Most stuff in Photoshop is a bitmap, which could also be named raster art. Or do you mean the art is converted to a printer dot pattern already?
Whatever, the best programs to make CP art in are Illustrator/Freehand. These vector editors give much sharper output with small file sizes. If you have Photosoup, you might have Illustrator as well. It's a free throw-in deal with Adobe Suites.