oh yea you need ot change them..disconnect the dsl and then change the IP address range of the router to say, 192.168.10.x series.
Assign the router a static IP address, say 192.168.1.2
Also do a DMZ onto the above IP address on the dsl.
Also please note that tomato on g125 doesnt seem to support intel 2100/220 series wifi chips, so lookout if you have any lappies with these chipsets.