Can't give you any exact website name off the top of my head, but I know for a fact there are LOADS of sites on the web offering used parts for Audi/VW.
Try searching for 'Audi parts' under google.co.uk. Most of these sites require you to fill in an online request form and send it to them via email (presumably as listing every part in stock would be a bit of a task). It's a good idea to find out the exact part number(s) of the item you're after; it will speed things up considerably.
Also try ebay; there's so much that comes in and goes out that it's quite possible you'll pick up what you're looking for at a good price. Again, just use your imagination as to what to search under, and you may strike gold.
Failing all this, speak to a few local scrapyards, and see if they know of any dedicated VW/Audi salvage yards - plenty exist - and do some ringing round. It may involve a little drive but you'd be surprised how many places exist that you didn't even know about.
And I must admit; even being blessed with the internet, I'll often find myself reaching for the Yellow Pages from time to time.
Hope this helps.
Andrew.
