If you're going to do a new install you don't need gparted, you can manage
partitions as part of the install process. Be extra sure to back up your data
because you're going to wipe your disk this time (in future you'll be able to
install the OS without touching the data in /Home).

Boot from the Live CD and choose Install, and follow instructions about setting
the location, keyboard, etc until you get to the screen that asks where you want
to install. The default is to use the entire disk (if I recall right), but at
the bottom of the screen the "manually select partitions" option is the one you
want.

From there on it's fairly straightforward. Choose New Partition Table to wipe
what you've got, then add the new partitions: you need a swap partition @ twice
your installed RAM, a "/" partition of around 20G, and the rest of the drive on
"/Home" (or other partitions as you desire). You can assign the mount points
("/" and "/Home" from a drop-down). I think the best file system to use is Ext4,
though others may have different ideas. This time round you need to format both
/Home and /, but in future, to state the obvious, you won't want to format /Home
(you will still need to assign it when you do future installs).