In addition to Foobar, you have the JRiver Mediacenter as another option for locally stored music. Connection from your computer to the Mac 7900 via USB A/B.
Using (for example) Quobuz as the source of music (PC app available), you can send the stream via USB to your DAC as well.
Give it a try. If you are satisfied with the soundquality, you will not need any additional hardware. If not, you may want to go with a dedicated streamer.
I am using an Android platform including USB Audio Player Pro going directly into the integrated amp via USB A/B (and as well via separate DAC to the amp).
It is all about personal preference.