I do a wiring kit for the gauges if you have not got the genuine Audi one.The T Piece i found mine on ebay it was about a tenner, the temp & oil sender you might find in a scrappy if they have any Audi 80's or coupe's.
You can buy senders on eBay.
Depends what gauges you have.I have boost, oil temperature, oil pressure.
stick up a pic of your gauges front and back til we see what you got.