I had two very old Belkin G Wireless Routers. They were the exact same model. I dont have them with me right now so i dont know their model but the closest currently manufacted model is Belkin's "F5D9230-4". They were both designed to function as stand alone routers. They had capability to link and work with each other. They have been very useful. I think they may have removed this feature, (WDS) in their newer models.
If you could manage to i recommend ethernet wiring instead of bridging, Or could you bring your modem closer to you 5 port switch. Does it have to be downstairs. If your modem is either DSL or Cable you should be able to have many more ports that they can use throughout your house. If a cable port or phone port is alreadly being used you could buy a $10 splitter so you could use your modem at that port as well.