optima batteries

[shavedchevy]

Just put a brand new stereo system in and have come to the conclusion that I need more juice to run everything. I have been looking at those optima batteries but don't know if I should shell out that much money for one or possibly two. I'm going to replace the alternator also. Does anybody have any suggestions on what I should do? I it sits right now, is that when I have my stereo on with some pretty good bass and my lights are on, it cuts out the stereo completely and the voltmeter practically reads the lowest it can.