change texture .dds to tga in all material of the scene

Hi,
I'm working on a motorcycle circuit and I follow a tuto to convert it.
In this tuto it is written to change all the .dds texture to .tga file of the scene.
The problem is the number of material and in each material there all the different shader (DX7 DX8 DX9).
The manipulation is easy :
open the texture choose the shader change the texture file and do the same for the next.
But I've 200 texture and 3 shaders each , my mouse will burn quickly.
Do you think it is possbile to resolve this by a simple script ? all the dds and the tga are in the same directory.
Thanks you.