You need a regulated 12v DC power supply. Ideally it should be wired directly to you cars battery. The amount of wattage you feel you need for your system is up to you, but looking at what you have listed there I would think that you would do fine with anything 90 watts or more.
check out the store portion of this site, should give you a good start.
Wether or not you want to do DC-AC-DC or DC-DC is also up to you.