Best possible digital output from a computer?

I've recently purchased a Yulong DAH1 Mark DAC (Chinese brand, not extremely popular). I have to say that so far I am pleased with the sound, and have been using the USB input which is fed by my personal laptop running Foobar or Media Monkey. However, I'm sure that this is not the best possible route, being that this DAC uses the PCM270x chip to accept the I2S stream via USB, which adds another thing into the signal path before sending it to the main AD1955 DAC chip. I believe the sound would be better through coax or optical, but what would be the best way to get a coax/optical output on my laptop? It has neither of those outputs built-in....

Thanks in advance.