Don't know if it is the best solution but you could get an Airport Express for $99 and wireless stream to the DAC (it has optical out). Works well with itunes. I think it will only handles 16/44 though if you happen to have a lot of high-res stuff. Also, there is a slight lag between when you click on a song on the laptop and when it gets to the DAC. Not usually a problem though (only if I am randomly shuffling through songs trying to find something I'm in the mood for, then the lack of speed can annoy me). If I am listening to a full album, it is not a problem.
Edit: The easiest solution is of course, to get an Macbook Air or Mac Mini.