Autocratic, I'm pretty sure that the D-series head bolts are reuseable, not stretch bolts.
What motor do you have? If it's the stock A6, you can toss on a vtec cylinder head. I would never pay to have head repairs done, because of the ready availability and inexpensiveness of replacement parts for these older motors. You can get them on ebay for around $80-90 USD, and if you can do the work yourself, you can keep the new timing belt, and get vtec. You'll need a new head gasket, but that's really it. You keep your dist, injectors, plugs, wiring harness, etc. It's also a great chance to change your water pump, oil pump, and front main seal. It's not too tough to do if you have any experience with it.