Jailbreak and unlocking ?s

[xcuses]

ok, so i accedently tried to upgrade my iphone 3g, its jailbroke and unlocked and i use it through tmobile. as you know you cant upgrade it without losing all that on the phone, ive been trying to unlock, jailbreak it and downgrade it back to how it was originally. i cannot figure this out. im on windows xp and all my iphone says when its plugged in is "connect to itunes" but itunes is telling me that the sim card i have is not lisenced to authorize. how do i get this back to what it was originally? please help!