It's the very bottom panel of the drivers side door, looks like it just screws off for replacement. Not sure how this happened (nor does my wife who was driving it ) but it needs replaced. Anyone know of the part number or where I could find it?

It's off a 2005 B6

 

You could call the dealer, ask about price and availability for that part. Give them your VIN number so they're sure to get the right one (they usually ask anyway). Once they answer your questions, tell them you'll get back to them about ordering it. Ask them the part number so they won't have to look it up again when you do.