That's a lot of power for a wall-wart. As far as understanding the restrictions: You'll need a switching style (instead of transformer style) power supply. Most all power supplies have their ratings listed on a sticker. You need one that supplies 12v with more power (in Amps) than you need.
First of all, I don't know why you don't just connect the devices to your PC's excellent 12v output rail. Anyway, the best source of high-power 12v power supplies are LCD monitors. Many of them (and most all of the LED backlit ones) use an external tabletop AC/DC converter that is 12v and can do several amps. Tabletop converter means that it sits on the table and has a cord coming out of both sides, one for the wall and one for the device. Laptops almost always use these; but they're usually 18–20v instead of 12v.
I hope that helps!
Don't forget to check voltage and polarity with a voltmeter before connecting your device!