Texture Application (Shift + A), select the face by left-clicking on it, then click the Fit button (one of the 6 small buttons in the Texture Application).
When the rotation is wrong, you can set your own rotation and apply the new properties to the face by right-clicking on it.
If the texture is mirrored, give it a negative scale factor, that'll mirror the texture.
That's probably all you need to know here. Good luck!