How do I do an upgrade to 12.10 using the iso downloaded from the ubuntu web site? I do not want to do a clean install as I do not want to loose my settings. I am afraid that clicking "UPGRADE TO 12.10" in update manager will upgrade the OS and all the packages and that this will take all my monthly data from my contract which is just 3gig a month.
I am not sure if there is a way to pre-download the files you need for the upgrade with an other computer. I am a afraid a iso can only be used for a fresh install (I could be wrong of course). I think most of the software needs to be re downloaded since these need to be the versions compatible with the new Ubuntu install.
however I wanted to mention that if you have your /home on a separate partition most if not all of your settings are stored on that partition. this means that if you do a fresh install, but don't format your /home partition (only point the installation to it) almost all your settings are saved. for example after the re-installation all my e-mail accounts and emails in Thunderbird where still present! this makes doing a fresh install not a big deal!
something can always go wrong so of course make a backup before re-installing!
If you do not have a separate /home partition I think you can rescue most of your settings by copying all of the folders in your home directory with a dot in front of the name (make them visible by pressing ctrl-h when in your home folder in your file browser). after your fresh install you copy the folders back and I think this will restore the applications settings. but try at your own risk ;)
Here are a couple of ways to do exactly that.