Check out the thread on the Nuforce HDP dac/amp. It is brand new & comes very close in quality to my $1700 Benchmark DAC1 HDR & it only costs $449. You have 30 days to figure out if it meets your needs. I've not used the Audio GD19 which I hear is very good but the HDP is a big step up from the Compas DAC in IMHO. I've been shocked at just how good it is & aonther thing I really like about it is that it takes so little desktop space. As an add-on the amp section's sound is as good or better than my DAC1.
Good luck with your search but just check out the HDP before you buy. It is killer for the price. If you do want to spend more add the Benchmark DAC1 usb. You can get it used for $900ish & as dacs go, that is about as good as it gets. Even couple the regular Benchmark DAC1 (which doesn't have a USB connection ) but a $20 Behringer u-control uca-202 (to provide usb linkage between the PC & DAC1 via it's optical port) and you can probably get a used DAC1 on AudiogoN for $700ish. If I didn't go for the new Nuforce HDP, then the latter is what I'd do. Spend the rest of the $1000 on good cables for your gear & you'll be a happy man.
Again, good luck. You have lots of good suggestions above. Just check out the HDP &/or DAC1 options before you buy. While you figure it out you might just buy the $99 uDac which is excellent for the price while you do more research. You'll get your money back real fast if you sell it here after you make your final decision. Heck, if all you have to compare is the sound that comes out of the PC, you'll think you died & went to heaven with the little uDac.