You probably don't need to change your back pads, unless you're a racer or have your brake bias set weird, your fronts do all the work. The rest of the stuff sounds like make-work to me, I wouldn't have any of it done except the front brakes, the bulb, and the oil.
Materials:
Brake pads (Front): $45.99 (
Duralast Gold/Brake Pads - Front (DG840) | 2003 Audi A4 4 Cylinders 1.8L Turbo DOHC | AutoZone.com )
Brake rotors (Front): $33 x 2 = $66 (
Brake Rotor - Front | 2003 Audi A4 4 Cylinders 1.8L Turbo DOHC | AutoZone.com )
Brake fluid: $7
Buy a one-man speed bleeder like this one, it makes changing your brakes super easy:
http://www.autozone.com/autozone/acc...ier=46839_0_0_
You might also need to either get a brake clamp or a brake tool, do some googling and find out, I don't know Audi.
Follow this guide to change your oil for about $60 in materials, and you REALLY need to do it every 5000 miles, particularly on a turbo car, so get this done first, even if you don't do anything else:
Audi A4 B6 1.8T Oil Change | Audiction.com