Samsung Galaxy 3: Problem with updating to Froyo using Kies

Friends,

I am trying to update the firmware of samsung galaxy 3 from eclair to froyo. But not able to do so using Kies.

Installed the latest version of Kies (Kies 2.0)
But the option 'firmware upgrade' is disabled.

Please help guys, the phone is in dire status, it has become very slow.

Any help or pointers is appreciated.