How to edit my partition in ubuntu

my hard disk capacity is 160 gb but after installing ubuntu
it shows a filesystem with 22 gb and another disk with 33 gb
so my remaining disk capacity is unused and not shown in media also
is there any way to bring that back and use that in the ubuntu???
my friend told some command like gpedit
but it doesn;t works
pls say me a way

GParted is also available on the Ubuntu install CD: boot from it as a LiveCD, open a command line, do

Of course, you should backup all essential data before you start playing with your partitions...