|You can do what you're asking. Essentially, you'll be extending your wireless network by adding what amounts to an Access Point (AP).|
Typically you would disable DHCP on the downstream router because you only need one DHCP server in such a small network. You'd configure the LAN side of it and connect it and the upstream router from LAN port to LAN port. You would configure the wireless network on the AP with the exact same SSID and other wireless settings (recommend using WPA2 encryption) with one exception, put the AP on a different channel. If the upstream router is on Channel 1, pick channel 6 or 11 for the downstream.
For a more detailed guide on how to add a second router, click on my name above in this response and read my “how-to” guide titled, “Add a second Router to your LAN”
You'll want to use the LAN port to LAN port scenario.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.