Okay so I'm running 1.1.2 fully jailbroken, activated and unlocked with the 04.03.13_G baseband and using an Australia sim card (Optus).

I want to update to 1.1.3 but keep my unlock intact. I've tried doing the upgrade through the Install.app but it says I need to be running 1.1.2 which I am so I'm not sure what's up there.

Should I download the 1.1.3 firmware file and do the "Option" "Update" thing in iTunes or what?

Please keep in mind that my technical knowledge is scarce!

Thanks so much in advance!