This requires the removal of the entire front end of the car apart, front bumper, rad support cradle, the radiator, a/c conderser moves out of the way but stays connected. Then raise up the motor using a jack after you unbolt the passenger side engine mount and remove it to get more clearance. Unbolt the alternator and slide it forward. Take the starter out as well and have it rebuilt too, as you don't want to be doing this twice if your starter fails in a month. It comes out after you take the alternator out.
If you have never done this before, but have good tool knowledge and are somewhat mechanically inclined, it will take you an entire day. You should also consider the timing belt/thermostat/water pump replacement as the majority of this dissasembly needs to get done again if one of those fails.
The first car i did this to was a 96 A4, 2.8. Now I rebuilt both the starter and the alternator on my wife's 00 A6, 4.2. I had to take the entire front apart anyways because I also rebuilt the transmission.
Sorry I didn't have better news for you.
2000 Audi A6 4.2, Still figuring out a ZF5HP24A trans issue.
2004 Honda Pilot. Wife's car. Bought in March to replace the Audi.
2004 Dodge Ram 2500, Cummins Diesel, All the mods listed on DieselTruckResource.com