Aww, you are though XD Well, there's an easier solution to that ;x;...If there's only a few colors, it should be a lot easier to use the fill tool.
This is an Icon Ripping tutorial. It does not tell you how to shade. XD
How to Rip Icons by ~LydiaEldafreya on deviantART
I think the last link I posted, you couldn't see the whole image. So I uploaded it as a tutorial. XD
Enjoy, people that use this.