12v power supply

If it's a external brick style power supply then have a look on ebay, you can pick them up for around £10 new, just search 12v power supply. Make sure the fitting is the same dimension as on the back of the box, and also check the amps on your current power supply, it will say something like 12v 3a

Also check the polarity of the centre pin,it will probally be live or +

And make sure its got enough ampage im guessing around 3A ?