Software version 5.x instructions
Go to this 2wire url
192.168.1.254/xslt?PAGE=C06
Click the configure manually option
Enter the desired ip address in the router address field
Enter the desired subnet mask in the subnet mask field
Select the enable dhcp option enter the desired dhcp range/pool
Click the save button

Software version 6.x instructions
Go to this 2wire url
192.168.1.254/xslt?PAGE=C_2_3
Click the configure manually option
Enter the desired ip address in the router address field
Enter the desired subnet mask in the subnet mask field
Select the enable dhcp option enter the desired dhcp range/pool
Click the save button