I just had a very quick play with Noel Carboni's tools (very good value for money) with your 2nd image data set, I hope you don't mind! It's not perfect by any means, but a quick press of a few actions in Photoshop CS2, all of 40 seconds "work", if that and voila...I'm not sure how accurate the colour is, and I think I probably softened the image detail a bit too much with my choice of actions that I ran...
http://www.macro-images.com/web/astro/M83_LRGB2.jpg
Let me know if you're not happy with me editing the image etc and I'll remove it from my website temp hosting area.
Dave