I used to run analog out w/my audiophile card to a reciever. It sounded "ok" at best, IMO. What sounded real nice was a stock Edirol UA-5. Feed it a signal via USB and then let it do DAC duties. It was a big improvement, imo.
I think you can probably find one on ebay for $225 or so. Not too much more than the AP external box.