Help with 2D shaders

I have a font shader file... which allow me to deny 3D text to be shown behind the wall...
i also want to give this 3D shader a Textural diffuse ... but i dont know how to write it....
i just figured out that i need a 2D property and my lighting ON for this job....

so i need to know to thing ...

1. How to apply my 2D texture (i know about colors)
2. How to make it the way not destroy (De-sort) my font shape