69 Cadillac audio

I've recently purchased a cadillac 69 eldarado. Im assuming im going to need to need the following,
Battery, Alternator all speakers and the wires for them, capacitor, im making a enclosure, and i already have a sub and hu.

If im running a say 1300 watt amp, and a 800 rms power inverter, a 200 watt hu, and some decent speakers (doors), will i need to replace the stock alternator and battery? I'd prefer not to replace the alternator if possible, seeing as they get Xpensive, if someone would'nt mind helping me figure out exactly what im going to need to replace, and the approximate pricing that would be great, i cant seem to find the amperage on the alternator in this beast, but i'll keep looking thanks.

Just thought of this, how expensive does dynamating get? im obviously looking into dynamating a 69 cadillac, that is about 19 feet long , its enormous, so im assuming im going to need alot. thanks 69 cadillac audio