Android Question

I have a Samsung Galaxy S3 Lte GT-I9305 & I dont have the update software function or developer settings. I'm on a 2 year contract with Orange/EE (U.K) which ends November 2014. I'm wanting to upgrade my andriod version to the latest one as im still on Android version 4.1.1

I know how to access the phone setting to restore to factory settings & custom ROM using Power off/on button, Homescreen button & Volume up/down button.

Any ideas how I can update my android version ?
I'm not sure how to do custom ROM and dont want to damage my mobile. If anyone knows how I can upgrade my android version or how I can get the software upgrade functionm to work on my mobile, It would be much appreciated.

Not sure if restoring my mobile to factory settings would sort anything out. I am missing out on new features due to not having the latest android version.
Updates are pushed (sent out) by the carrier - that would be Orange, in your case. They may be a bit more cautious than most, due to all the bug reports on the first update (enough that I call it a bug, not an update), and the current emergence of bug reports on the "fix", sent out to fix the bugs the first bug ("update") caused.

If you don't get anything by the new year, I'd contact Orange and ask what gives with the "no updates".