can I update to jelly bean or ICS

My lg optimus net is rooted. After rooting I can see an update available. Will it be an updated version of my current OS ginger bread itself.

Or can I update to the latest android version as LG is not providing ICS or jelly bean officially?
I have installed some fonts in my phone after rooting and partitioned my sd card too to install apps in 2nd partition. Will I lose these if I update??
Right now am not thinking of a custom ROM.