The user's guide for your router can be found here (PDF):
Based on a quick look at the device, I don't think it can do what you need it to. There are two issues:
- The device is intended to use the dsl port as the WAN port, so the factory firmware won't support dhcp to just the remaining ports. More importantly, it only supports the layer 3 (router) functions you need to route packets correctly between the local network and public internet between the ports on the lan side of the device and the dsl port on the WAN side. It won't know how to treat one of the lan ports as your internet connection.
- All the LAN ports likely have the same mac address, and this device is unlikely to support mac spoofing.
That said, you might get lucky and it could work out one of two ways:
- A more thorough reading of the linked document might prove me wrong (though I doubt it).
- You might be able to load something like dd-wrt, open-wrt, or tomato on the device, at which point you have a pretty good chance of making this work.
Also, you can get a wireless router off the shelf for <$40 just about anywhere that will do this, or for <$20 if you know where to look online (newegg.com or amazon would both do this).