well, since u used a poly mesh, you need to lay out the UV's of the geometry.
laying out the uv's can be complicated or easy, it deppends on your mesh. since this is a fairly simple model, it should not be so difficult.
a simple cylindrical map should do fine for the head, and then apply other mapping techniques as you see fit, and work the uv's to be a nice continious lay out.
then import a snap shot, or bake out a reference texture map of the mesh to use as a guide as you paint the textures in your favorite 2d or 3d painting application.
for more guidelines, there are great free tuts on 3dtotal's website or learningmaya.com for more indepth step by step tuts.
good luck.