WIFI & hotspot problem on my iphone 5

Hello everyone , I have a big problem on my new bought iphone 5 , it's WIFI signal is very very slow and Weak ,
and don't see many of access points around it and it's hotspot works very bad and random .
my device iOS is 8.2
I reset my network setting post week but it didn't resolved yet :-(
whiles my sony xperia go htc hd2 device oyr my notebook, can see all of access point wifi lans around our home ...
Please help me ....

thanks a lot