freezing iphone 4s with very weak signal including on wifi.

hi i really need some advice please......

i have an iphone 4s, less than 12 months old. phone keeps freezing even in the middle of phone calls. Also my signal is very poor struggling to even get 1 bar at times, constantly waving phone around :-) and my wifi signal is poor even with me sat in the same room as my router. Both my children have blackberry's and their signals and wifi strength is great so i no its my phone. So after talking to apple i have backed my phone up on itunes and icloud and restored back to factory settings, so far going good until i try and restore from back up and ive lost all my music, pictures + apps. but kept my contacts and text messages. What can i do? Can someone Please give me some advice, ive been at it since 9pm last nite :-(.