I just discovered a pretty deep dash on the passenger-side skirt of my A4 the other day while giving it the inaugral wash. It's probably three or four inches long and fairly deep. I was a little horrified but since it's not that noticeable I could leave it alone... But now I know it's there ergo I want it fixed!

I'm guessing I should get some fine-grade paper to sort out any rough bits on it, then fill it with some kind of... Filler stuff and then paint it with touch-up paint?

Any suggestions on which products I should use for a job like this? Sorry, complete newbie when it comes to this kind of stuff.