set it at 192.168.100.2 then set the ip pool to start at 192.168.100.10 to say 192.168.100.50 cheaper routers will not support many more than that and it doubtful you have more than 50 devices in your house, in the setup page set the ip to 192.168.100.2 then hit apply settings and reboot the router, after you log back in you should be able to set the ip's to the higher range
you could always make your own router with an old pc with 2 network cards and run ipfire, ipcop etc