I finally have it up with its latest firmware in the same location/place. Surprisingly, it worked better than my old Linksys WRT54GL router's wireless even in the far away lowerlevel family/living/den room. It's not perfect, but it worked and speeds were decent. A few packet losses here and there, but not bad like the old router. Even watching a 720p YouTube video seems to do well. I even tried closing doors to see if they affect the wireless signals. Still good!
However, it has to be on 2.4 Ghz and not 5 Ghz (didn't know you can have both running at the same time -- now I know why it is called dual band).
5 Ghz wasn't strong enough for closer distance rooms too (worse than Linksys WRT54 GL's!).It doesn't look like the unopened Netgear's universal dual band wifi range extender 4-port wifi adapter is needed now (will return it near its 30 days return).
Also, nice GUI. All fancy now. Lots of features (no time to try them too). I wonder how Linksys' newer routers are now. I used to use Netgear RT311 that didn't have many features. I used use its telnet (preferred over web GUI).