You need to change the router IP to something different - so for example your router setup page appears when you type 192.68.0.1. Then type that and log in to your router and change its LAN IP to say 192.168.0.111 and save it - you may have to reboot it. Then you should be able to type the original address of 192.168.0.1 to access the gateway. Depending on what is setting the IP addresses for your network you may have too or should set the IP address you set for your router as reserved in the DHCP settings of the device providing the DHCP.