The directions Axxeon has really need refined.
Basically a home 'router' hands out DHCP - gives IP addresses out. By default, routers have the IP address of 192.168.1.1 or 192.168.0.1 - so when you connect two on your network, they use the same IP address and cause conflicts.
You would want to take your second router/wireless router and connect directly to your computer with the patch cable. Log into the router, assign it an IP address 1 higher than current (192.168.1.2 or .0.2). You will want to configure DNS to be pointing towards your other router (192.168.1.1). Disable DHCP on the router.
Your router will now act as a switch. If wireless, configure the wireless how you want it set up. By disabling DHCP, your 'router' will pretty much become a switch unless you plug into the WAN/Internet port on it.