"Bridge Mode"

I just installed a Dlink router and WIFI range extender. Dlink is telling me that I need the cox router/modem set to "Full Bridge" mode and that I need to be able to receive "Public" IP addresses (e.g. 72.193.9.103) instead of Private addresses (e.g. 192.168.0.1). My last conversation with Cox tech. support was that the default mode is bridge, however, on a hardwire connection to the cox router/modem, my default IP address is 192.168.0.1, which is a private IP address, not a public IP address. How can the router/modem be modified to get public addresses?