eMac and airport base station problems connecting to internet

I need help setting up my mom's eMac to the internet via an airport base station. The main computer that is hooked up to the cable modem is my new iMac.

Does anyone know the settings I need to input or where I would find them? I'm at a loss for what to do because usually it all works when initially connecting.

Any help that anyone can offer will be greatly appreciated.

The airport will be connected to the emac and then hopefully it will then connect wirelessly to the imac. The emac is in an office and not near the cable modem that the imac is hooked up to.

I have tried the setup assistant but I can never get it to work for me.

Any help to resolve this problem will be greatly appreciated.