Confused - how do i get a static ip range through my router?

[rudeboymcc]

Hi. I'm having trouble with BT Business broadband. I've got three static ip addresses and a Netgear DG814 modem. The problem is when i select static ip mode on the router, i get three boxes, ip address, subnet mask, and gateway address. then two more for DNS server. I can't see how i can use all three static addresses if i can only enter one in the netgear router?