Unless they're willing to give you more then 1 IP, you don't want to disable the routers DHCP server if you want more then 1 computer to get online. I think they mean to use PPPoE or some other method on the router and not use DHCP on the WAN. But if that was the case, they wouldnt have DHCP servers. So I think you got some bad info there. Could you give more info? Who is your ISP? What other equipment do you have?