Use Internet Sharing to share Ethernet connection to router?

[iModFrenzy]

Okay, so the Wifi signal from my router is absolutely terrible on my iPhone and other devices in my room.

I have a iMac in my room that isn't used that often that gets great signal. I also have a spare router. I connected the router to my iMac(using the yellow port on the router) and turned on "Internet Sharing".

But it doesn't seem to be working. I usually can plug this router in to my main router and it automatically works so I think it's an issue with OS X.

Any help is appreciated, thanks!