The speakers will work with any kind of amplifier. If you want great sound without spending silly money, NAD is your best bet, or Rotel.
You can use your computer as a CD player, however remember that when you read/play a CD on your Mac, it's much noisier than doing it on a normal CD player. You could always just rip the CDs into iTunes though, which can still sound very good and play the music without the CDs.
The speaker connections aren't a B&O connection, other companies used them too, but B&O was the most prominent. You could try your nearest B&O dealer, and just cut the other end off the cable and wire it directly into your amplifier! Very easy to do...
One thing to check with the speakers is that they aren't suffering from what's called Foam Rot. Essentially, the rubber/foamy bit around the bass speaker can decay over time, and will rip itself to bits as soon as you play music. To check for this, take the top grille off the speakers, and just check the surround yourself. If there are any holes in it, or it seems particularly fragile (test this by gently running your finger around the edge, but don't push on it or you could damage a perfectly good speaker). If the surround crumbles away, or has already done so, then you need to get replacement bass drivers. Not sure how much they are for C40s...