Why is my sound system draining my battery?

Ok so I have a big problem I need fixed. I installed 2 12 inch kicker L7s with an 1800 watt amp and an 8 farad capacitor that I don't know is working because of no display on it. I installed in friday afternoon. So today when I go to start my car, I put my keys in, I can see my car gauges but I can't start my car and it only clicks when I try. I have a civic 05 LX. Should I get a new battery better than the stock one? Or should I fix my capacitor? Any help will be great thanks!