Thanks very much everyone.
Phil, I got pretty lucky and found a coin graphic. It actually was shaded very well. but the steps I use are normally the same for any other model that I create.
1. Identify the various shapes from the graphic you are working with. Start with the base shapes and work toward the smaller more complex shapes or work from the base and up to the highest points.
2. Create vector of those shape, in this case:
a. The head
b. The hair
c. The face
d. The ear and all the shapes inside the ear.
e. The chin the nose the eyes and so on.
3. Create model from bitmap. Duplicate the texture and hide.
4. Cut the major textures away; the hair the ears and face.
5. Now create the base shapes from the vectors previously created and build your face to give it heigh and dimension.
6. Bake those components together (component by component or all at once) and use the shaping tool to blend, smooth, smudge, remove or deposit as need to make up the difference.
7. Overlay the textures previously created and and bake do some final touch up and your done. If deeded use the duplicated texture and continue to build on your model and sculpt it into the shape you want.
I was fortunate with this one and only had to create a few base shapes and was able to build on the bitmap model to sculpt on.
I hope this helps someone.