You should be fine mate as the current draw from those items is pretty low.
If I were you I would wait until you start seeing signs that your battery cant cope before you splash out on more expensive charging methods.
A lot of people purchase split charging systems for the hell of it when really they dont need it.
It also depends on how loud you play your tunes etc. But I reckon unless you were powering more subs youll be okay.
Power up all your stuff and put it a full volume and go for a drive at night. If your headlights dim or flicker then you don;t have enough power.
For the record Im running 3 amps (240w, 600w and 400w), 2 12" subs, playstation, screen, tv tuner, 4 6x9s, 6" front components and soon dvd player and my standard battery is fine.
Hope this helps