Helping out a friend who is trying to get wifi working in the back corner of his house from his office (where the DSL and router are installed).

He's got an old Belkin router at the moment (11g only) with a single antenna.

I've looked at relocating the wifi to a more central point in the house but that's not currently possible so am thinking that a newer, higher powered and better antennae'd router is the best option. 

Any recommendations for a Telecom compatible router / switch / access point with excellent range?  

Or alternate suggestions (my experience with range extenders is poor but several years old)?

Cheers,
Adam.