my be you can serach app standard from google android
Please, what new stock rom Agustus or July in SGY
You can update the firmware via the phone, subject to existing Internet data packets, by the way:
go to settings> go to down and select about phone> software update> update
n you can download DXKL3 here on Flash via CWM Alfa CWM Alfa...
n you can download gtalk.apk in this here Gtalk
maybe your firmware is not work good, change your rom use.