Powering Sparkfun Triple LED via battery

Simple question. How would I power this?

http://www.sparkfun.com/products/9748

Using as a vehicle headlight, needs to be mobile. Says 7v to 30v in, but at 650ma each LED I think a simple 9v alkaline battery wouldn't last long and as the battery depleted the voltage would drop. Looking more at a lithium ion rechargeable type battery, and since it will be attached to an arduino (3.3v or 5v, will decide based on the lighting power) I think that could be done. I would like to also power an Arduino with the same source if possible. Also want to power 50 or so super bright LEDs (2.4v 20ma) (http://www.sparkfun.com/products/9660) preferably with the same power source. First battery powered Arduino project and getting a bit ambitious.

Would this work?

http://cgi.ebay.com/12V-DC-6300mA-Rechargeable-Lion-Battery-CCTV-Camera-/300496655563?pt=US_Batteries&hash=item45f6ff14cb

-Nick

That battery is half the size/weight that a 6300mah battery should be. Very dubious that it's rated properly.