If you only require the systems connected through the Ethernet ports of the Wireless router to share the internet connection on the Windows 7 PC, you can connect the Ethernet port of the Windows 7 PC to the Ethernet Port on the Wireless router as you are doing now. Just make sure that the TCP/IP settings on all systems are static with the gateway set as the Ethernet port of the Windows 7 PC with all the systems configured to be in the same IP subnet.