Nice, I ordered this 7watt amplifier.
http://electronickits.com/kit/comple...l/CANUK153.htm
Haven't hooked it up yet, so I'm not sure how well it'll do. But, if that 3 watt amplifier is doing you satisfaction, hopefully this will be great. It requires 12-16volts, but that's for moderate to max output. I'm currently researching for a diagram to increase the voltage output to the amp with transistors before the power input. Maybe I can get the 7.2v battery amplified to 10-12v without having to use a secondary battery for a stronger output. I'm no electronic engineer, but I know it can be done.