The answer is really that if you want the receiver to have internet access you need a network, ie get a router.
Alternatively if you are very confident with pc's, ip's, gateways, etc, you can try the internet connection sharing method through your computer but its not going to be ideal. You need to connect your receiver to the ethernet pci card with a cross-over cable, and dont use the serial port.
Your pc will then have to connect to the net by usb modem or whatever else you use. Then set up your internet sharing in your operating system to use that net connection, then enter chosen settings into receiver to direct it through that gateway.
In reality if you want more than 1 pc or other item to have internet connection you simply need a router.