OK - presuming that your Netgear router manager is the same as mine...
Type 192.168.0.1 into your browser. At the prompt, User is 'admin;, password is 'password'.
On the left panel, click on 'LAN IP set up'
Change the IP address in the top box to, say, 192.168.2.1
A bit further down, change the 'starting IP address' to 192.168.2.10, and the 'ending IP address' to 192.168.2.254.
Click apply. See how that goes. Don't forget that to get back to the router page you'll now need to type 192.168.2.1 in your browser.