Porting a portal 2 model and texture into a css map?

I have been trying to port a portal 2 model and its accompanying texture into the hammer editor. The map is for gmod, which as far as I know the models can be used but need to have the .vtf files edited to the older version. Any help would be greatly appreciated!

For me Portal 2 props work perfectly fine in GMod, so they ‘might’ work on CS:S if you port the right .vtf’s and .mdl’s from Portal 2.

You can try ‘VTF Version Changer’ http://www.tophattwaffle.com/downloads/
I used it for CSGO textures, Portal 2 should be similar.

Would VTFedit not do exactly the same thing using the advanced tab when importing a tga?

I don’t know, but how do you get textures in tga anyway?