There are lots of options, limited only by your budget and desire/ability to tinker. You have the bare minimum setup and it can certainly be improved. The Computer Audiophile forums are a good place to discuss with folks who are open to these issues and have lots of experience. I went from a Windows laptop to a server to a better server, used different cables, added external signal improvement devices, and linear power supplies. Each was a substantial improvement to the sound. Streamers are also a possible route, and these can also vary from a simple basic setup to a more complex one, with similar sound quality improvements at each step.
