Your camera use a NH-AA-DA battery.. The NH-AA-DA is a simple a nickel metal hydride, AA sized cell. Each one is rated @ 1.2v nominal. Any nickel metal hydride, or even nicd (nickel cadmium for that matter) from Wal Mart will work just fine. I searched Google for them and found plenty of Sony branded "NH-AA-DA" batteries for $15.99ish.. That's a royal rip off, cuz they should be about $4 per cell.
However, any plain old Alkaline AA cell is going to work just as well, just not as long. The voltage the cells provide has NOTHING to do with how long they last. The mah (milliamp hours) are what dictates how long they'll last. A 2100mah battery will supply 2.1 amps for 1 hour. A bulb from a car tail light pulls ~5 amps, so it would suck your NH-AA-DA dry in 22ish minutes. Your camera shouldn't pull near that many amps. If it does, it is defective and a fire hazzard.. Call tech support.
oh and FYI... No single NIMH cell puts out 2.4v, the technology simply doesn't work that way.. If you see a number greater than 1.2v, it means multiple cells are used in the battery pack.
My digital camera started turning off and on at will, even after recharging the batteries that came with it(I'm not sure there isn't something wrong with the camera now). Idiot that I am, I threw away the batteries(2100 mAh) and replaced with normal ones. :duh: Turns out my wonderful sonycyber-shot, DSC-P72 runs on 2.4V, so regular batteries last for only a few shots! :thud: 
c: 
