Root Rooted vodafone magic how to get to 2.2.1


i've got a rooted uk vodafone htc magic which is still on 1.5 as i haven't used it for ages i now have a galaxy s & was keeping it as a back up.
anyway my mum was recuperating after an opperation somewhere & she couldn't use her laptop until i lent her my galaxy which has the wireless tethering which she thought was great.
so now i want to update the magic from android 1.5 to 2.2or 2.2.1 which ever it will go to.
my main problem i think is i am no longer on vodafone & when i put my orange sim in it doesn't update or anything so do i need a vodafone sim?
also if i do a factory reset will it lose the rooted part of the phone ?
thanks in advance :)