Antoni,
I am not really a person qualified to give a foolproof reply, but wondering if you could possibly do what I have discovered will work if, and only if, you use a good quality home theatre amplifier. If you use the digital optical out from your computer to connect to this amplifier, then you can utilise the DAC in the amplifier, thus giving no latency or distortion from inside the computer. Since you are at present only interested in stereo, this method avoids the need to buy an expensive sound card.
Another method with which I am still struggling is to use an HDMI lead from computer to HT amplifier, this enabling multi-channel use (there was a series of postings a few week's ago on this). Possibly one of these hauptwerk users could advise a little more detail on this?. These high-quality sound cards seem to cost more than the computers themselves.
Charles