Maybe there's a way making a texture emit light? Or something like that?
Texure lighting? You mean the ONLY way you SHOULD be lighting maps in Goldsource?
In your compile tools folder, you should have a "lights.rad" document that controls the texture lighting values when you compile your map. You can edit this with notepad. It will have lines like this:
TEXTURENAME 255 255 255 2000
TEXTURENAME2 128 255 0 200
and so on.
Seriously though you using texture lighting for most of your map. Entity lighting in Goldsource rarely looks good.