Just visit that site and plug in your model/serial number (which would have helped here, btw). You could also send them an email too.
I am seeking a new AC-DC adpt Input 230-240V 50Hz 150 mA
Output 18v=800mA 14.4VA
htis was used for my wireless dell surround unit, need it for UK useage , any tips please as to what is available to buy?