Texturing both sides of a flat plane

Hi guys, as the title stipulates, I am looking to apply texture to both sides of a flat plane. I am on a Tris limit so extruding the mesh and applying texture to it is out of the question as it duplicates the tris value for that area, so I’d like to keep a flat plane and apply texture to both sides. I have tried searching for the solution but everything I find applies to outdated versions of blender. I am currently using 2.69.

Thanks in advance.

Thank you Richard for your reply.
After following the links and reading the tutorial I’m not sure this will help me.
The texture and the model needs to be separate, which means I have a model file (.smd) and texture file (.tga). This requires me to UV map, unwrap, bake the model and then apply texture externally. Once textured I can then import the .tga texture to Blender using the UV/Image editor and apply to my model.
But of course the texture only applies to 1 side of the plane which leaves the inverted side of the plane see through.
Judging from what I read in relation to adding nodes is that the texture is instantly applied to the model, not separately.

I really hope this is making sense.