Touchwiz deleted Galaxy S Duos. Phone doesnt work beyond language setting
Grab yourself a stock-firmware from sammobile.com or from the xda
forum.
Install Odin v3.XX on your PC, start Odin and boot your phone into the download Mode ( Volume Down + Power ) 
Use Odin to flash the stock firmware onto your phone, wait until it is completed
Restart your device and set it up from the beginning
Optional: Root it again and next time - install a different launcher - you don't need to deinstall the whole touchwiz framework - I'm surprised that the systemui was still funcitonal.