how to jailbreak and unlock iphone 3gs?

[Jorge]

well i bought an iphone 3gs 16gblike two weeks ago, it was already jailbroken and unlocked, it had installed the newest firmware (3.1.2), it was all fun until today when i tried to restore my iphone with out deleting all the data, and it got stuck, now i am notsure what to do, because if i restore via itunes i would need to activate it and i dont have an att sim card, what should i do? i am afraid of not being able to unlock the iphone anymore, i am not sure what baseband it has because my iphone is stuck recovery, i cant install blackrain because like i said my phone is stuck in recovery mode the one where that shows the apple and there is a bar below it but it only fills like 1/5 and then it reboots and repeats the same process over and over again