Help Me With Everything Needed: Computer Audio

I'm ready to set up a computer audio to stream music from my favorite websites. I'll do ripping and storage later on.

I want to try and stay around $2k for everything and connect it to my stereo rig.

My audio setup is:
Amplifier: Cary A-306(Class D)
Preamplifier: Classe CP 35
Speakers: Mirage OMD-28
Sources: Krell SACD Standard Mk3, Jolida JD 100 modified, Don Allen Marantz Changer

I've done a little research. I'm thinking to get a laptop or Mac Mini--whichever is less complex.

I'm thinking of the mhdt Havana DAC

Can you suggest a reasonably (think good but inexpensive) cable. Which is best, glass toslink, usb or other---I don't know all the jargon...

Please tell me everything I need to purchase to hook it up to my stereo rig.