I know how to hook up a basic mobile DJ system with one amp, however when I get 4 powered speakers and a sub, do I need 2 amps or 3 and how do I hook them all together? I have this basic system below.

1 Alto MAC 2.4 Amp.
Denon DN-D4000 dual CD player
Behringer VMX-300 mixer
2 customed made speaker self powered around 850W each.

Currently I use bannana cables to hook up my speakers to the amp.

Next question:
Anyone know how to tell exactly how loud (in watts) my custome speakers are? The gentalmen that sold them to me told me they are 850W each. I don't know if he is lieing or not, but I'd like to find out exactly wattage