How i can export textures

Hey guys, im new here and i want to know how i can export an texturemap from unity3d in an png/raw rgb (ROMM) format.

An example, i want to have texture 1 (Grass) in unity3d with the rgb (ROMM) 1 1 1,
and the texture 2 should have rgb (ROMM) 2 2 2. (png/raw)

What I mean is here better explained :

I want the output file in png/raw if possible.

I hope you can understand my english. :confused:

I dont know if im here in the right section, if i arent,
help me to find the correctly section.

I found something http://forum.unity3d.com/threads/18096-Is-it-possible-to-export-terrain-splat-maps
but how i can run a script in unity3d? -.-