if you brought the wireless router simply to have wireless connections, then just dont use its router side,
internet
| (wan plug not used)
| |
router1 router2(wifi)-~
| | | | | | | |
| | | +------------------+ | | +-- pc on router2 ~-pc(s) on router2(wifi)
| | +-- pc on router1 | +-- pc on router2
| +-- pc on router1 +--pc on router2
+-- pc on router1
Just make sure you turn off the DHCP server in router2, and set it a fixed ip address on the lan out of the dhcp assigned address range
ex
Router1 = 192.168.1.1
Router2 = 192.168.1.2
Router1 DHCP assigns IPS from 192.168.1.101 onward
Router2 DHCP disabled
Essentially u turn router2 into a wifiHUB
A pc on router2 or the wifi needing a IP address when it starts simple dhcp requests one, it flows on to router2 and out again to router1 whcih answers it.
[edit]
this way u also dont need to worry about forwarding any ports in the second router, as your not using its routing anyway.