23" Cinema HD Display w/ 21.5" iMac

I have a new iMac 21.5" (w/NVIDIA Graphics Card). I want to hook up a Mac 23" Cinema HD display as a second monitor. The cinema display was recently purchased from a friend and was working when I got it from them. I have upgraded to El Capitan.

Can I connect the cinema display to my iMac? If so, what cable should I use and will I get full functionality?

Where can I buy a replacement power supply?

Thanks!

Eddie