I don't have any experience with repeaters/access points, so I just want to double check on this. I need to connect 2 offices that are in the same building - but can't use wires. The TRENDnet TEW-430APB AP has WDS Bridge so I believe this will work? the network on the left will have full access to the Internet and network through the network on the right?
Since I read here the other day that US cable MODEMS only allocate one IP address, I think the network on the right should have a router instead of an AP. Then it may work. Have you considered powerline networking?