Setup question

Currently using imac with all my audio in apple lossless. Would like to go to usb based dac but my audio system is in another room and I cannot directly connect. I'm using a sonos system to access but however it could have better quality and I'd rather not do upgrades to sonos. How can I do this and retain the ability to get music into my ipod from the imac? Buy a new mac mini? Suggestion are appreciated!