Hardware :: Unable To Know Netgear Router/Airport Xtreme Base Station?

I have been struggling for ages to get my Internet DSL access through all the rooms in our house but lamentably failed so far.

My main router is a Netgear Wireless DG834G V2, 54MBPS. 2.4 GHz, 802.11g that works perfectly within a limited range.

Hoping to extend my range of access, I have added to it my old Airport Extreme Base Station 54 Mbps 802.11g, connected with an ethernet cable.

But still, the connection fails to connect in one bedroom upstairs, only a few feet away from the bathroom and other rooms that receive both a clear connection.

I tried connecting my some 4 years old Airport Express in this bedroom but I could not succeed having the green light ever?

Can anyone helps with a simple, clear and detailed explanation on how to process to set-up this system right?
Do I really need to have the Apple Extreme connected to the Netgear?

Should I replace the old 834G router by a more powerful one and which model would you recommend?
Or should I scrap Netgear and use only Apple Extreme Base Station (or the latest model)?