3gs Jb and unlock help

[Miz.Michele]

I'm on 4.01 5.13.04. I had jb'd with the very easy slide to jb and utrasn0w. I'd like to update to 4.1 or 4.2. I need the unlock since I'm on tmobile. My shsh is saved with tiny umbrella and shows up in cydia.

How do I do this? Custom firmware? From where? Then shift and restore I'm iTunes. I'm on a window pc.

Thanks

[M3th0s]

iClarified - iPhone - How to Jailbreak and Unlock Your iPhone 3GS Using RedSn0w (Windows) [4.2.1]
That should work like a treat
Good luck!