You will need to install a larger alternator not more batteries. Search for 3g alternator install they make a 130amp that can easily be found in salvage yards for cheap. And the work needed to install one isnt too complicated.

Yea sounds about right, but what I don't get right now is why my car isn't turning over at all it just clicks from the solenoid from time to time. Maybe a loose wire of some sort..

Sounds like your right on track with a loose or corroded wire. could be a bad solenoid too though.
http://chrisb.users.superford.org/Bronco/Projects/3G_Alternator/3G_Alternator.html
That's a pretty good write up on a 3g install

I just replaced the positive battery wire and solenoid and bought a new battery. -.-

Is the starter bad?
 

"I just replaced the positive battery wire and solenoid and bought a new battery."  Do not forget the negative battery cable and its connections.  Since the components are in series, any one could cause excessive voltage drop (like weak link in chain syndrome).
 
Just guessing, the square thing could be the voltage regulator (bolted on the sheet metal).  If the cylinder thing is bolted low on the bellhousing, that would be the starter.

Clean & tighten ALL battery connections, grounds, starter & solenoid positive connections & see what that does. You have a bad connection or corrosion somewhere.
 
I've run as much as 2200 watts, 4 subs, 6 midrange & tweets off a stock GM alternator & 1000 amp battery & never had issues. If your lights dim with heavy bass thumps try a 1/2 Farad cap wired to the amp.