If I was totally stuck with that phone, then I would attempt GingerBreak. But like others said, it would probably die in a month so I would return it and buy an used but true phone.
Sent from my GT-I9300 using xda app-developers app
Samsung Galaxy S III 16 GB White(again, so bored of Samsung)
Galaxy Note II 16 GB
Samsung Galaxy S III 32 GB White