where do I go to change the sensors out on the front of my 2001 audi quattro on 2001 Audi Allroad Quattro

dash light flashes-pump sounds,front end not going up at all, diagnostic reading says replace front suspension sensors

Asked by for the 2001 Audi Allroad Quattro
that could also be a circuit malfunction have it ck'd by a audi tech this is complicated system