Exclamation Emergency Please ... ATT Galaxy S3 Stock Firmware jelly bean needed

Hello Everybody
I need an urgent help please ...
my phone is not working i need to get ATT Galaxy S3 Stom Firmware android 4.1.1 or below on a fast link please
I searched everywhere i only got one link which tells me 12 hours left for download to be completed and my internet is a high speed internet so please a fast server

your help appreciated