If all you want to do is extend the power cable, you could use twisted pair, lamp cord, or even four conductor thermostat wire from Home Depot etc. Just make sure you keep the polarity correct from end to end. How far do you want to extend the camera from power supply?
Long runs may require larger gauge wire or a power supply with higher output to overcome line loss. Since you didn't indicate the distance; 16ga or 18ga lamp cord may be easiest and simplest to get.
If you want another power supply, take you old one to Radio Shark and let the clerk help you. You need a 5VDC 2 amp supply with proper sized coax connector with the center pin positive and barrel negitive for polarity. This is the most common configuration for coaxial power connections.
PS Ask your brother for help.