You can do that using the dd-wrt firmware, but I am not sure about the buffalo firmware.
Hey eddy get the budget buffalo and flash to the tomato firmware, and see your worries fly away 
tomato & ddwrt firmware has that feature.
wat abt the WHR-AG108..
thats available for muh cheaper right..arnd 2.6k..
how does that compare to the HP-G54..?
Are you talking about WHR-HP-AG108?
Thats even more expensive than this one last time i checked.
And it was not in stock anywhere.
WLI-U2-AG108 is available for 2.6k but that USB wifi adapter and not the router / ap.
I paid about $53.00 for the WHR-HP-G54 at NewEgg about a month back, this works out to about 2,177R… not so bad.