In practice there should be only one active router on the network. The proper configuration would be:
Cable/DSL modem connects to router's WAN port via Ethernet cable. The router connects to network devices either through an Ethernet cable from the router's LAN ports or wirelessly.
So for your system you would connect an Ethernet cable from one of the NetGear's LAN ports to one of the LAN ports on the TC. In this configuration the TC will act as an expensive switch. IP addresses will still be assigned by the NetGear device.
However, in my opinion I would dump the NetGear device and replace it with a plain modem (no router.) Then utilize the TC as your local network's router. This way you get a better modem to go with an Apple router/TC.