Wireless router setup,...as AP or repeater?

I'm having a bit of trouble figuring out the precise setup scenario for my new Rosewill wireless router, which as the pic below shows, I want to use in another room from my ATT DSL modem (with built in wireless capability). It will provide network connectivity to my wdtv live media player .....The setup routine in the manual for the Rosewill router requires it to be connected to my pc's ethernet port AND the DSL modem. I think this initial setup configuring is what is giving me headaches...The problem seem to be exacerbated by the fact that how I want to use the router is not specifically addressed in the manual, so I'm unclear about the setup routine...is it setup as a repeater or AP? So far, connecting as the manual suggests, I eventually lose connection to the router's setup configs or lose my DSL connection by tinkering with settings there, trying to get everything communincating, and have the rosewill router show up as a device on my network from my pc.....if anyone could take a look at the pic, and give some pointers on the initial setup, I'd be appreciative. Thanks...