HELLO,PROBLEMS WITH IPHONE 4 S

HELLO, I'M ITALIAN. MY PROBLEM is THAT I BOUGHT AN IPHONE 4S FROM ebay austria. however IN ITALY I CAN NOT use that,

BECAUSE IS LOCKED T-MOBILE. I HAVE ALSO UN T-MOBILE SIM CARD AUSTIA, BUT HAVE NO SIGNAL IN ITALY

.... PLEASE IF YOU CAN HELP ... THANK YOU