Mahtli69 is right on. There's almost nothing you can do to get a small web JPG to print out "nice". Once the file is compressed it is small forever. That's the problem with pulling images from the web. The majority of web images are small and lo-res (so they are quick to load on the web pages). The majority of them are not of print quality.
I suggest you go to the library, do some hunting for books or magazines with the people you are looking for, then scan these images in yourself at a hi-res (hopefully you or someone you know has a scanner). You may have to do some photo editing to get the settings right, but at least this way you can scan the image in at a much larger size. Make friends with a graphic designer. They'll help you out.