Do you know the model number? I wouldn't imagine its much. 1amp would probably be sufficient based onw aht I see for other cameras. You should be able to find one from some old electronics.

If you are testing it on a bench supply remember that it needs to be dark for the LEDs to come on. This was a gotcha for me with my outdoor analog cameras because it was all good during the day, but as the IR lights came on at night it started to sag the powersupply voltage and they all got dimmer as more came on.