I have installed Ubuntu 13.04 besides Windows 7 with initial space allocated as 18.2 GB. Now I get a warning to increase the disk space and I wanted to increase the disk space for Ubuntu. My total hard disk space is 320 GB and as seen from other posts, when I execute the following command in the terminal :

sudo fdisk -l

I receive the following response

Disk /dev/sda: 320.1 GB, 320072933376 bytes

255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk identifier: 0xcfc64c27



   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *        2048     3074047     1536000    7  HPFS/NTFS/exFAT

/dev/sda2         3074048   596467711   296696832    7  HPFS/NTFS/exFAT

/dev/sda3       596467712   625139711    14336000    7  HPFS/NTFS/exFAT

I ran df command and got he below response :

xxx@ubuntu:~$ df

Filesystem     1K-blocks     Used Available Use% Mounted on

/dev/loop0      17753424 14090256   2754676  84% /

none                   4        0         4   0% /sys/fs/cgroup

udev             1861852        8   1861844   1% /dev

tmpfs             374280      900    373380   1% /run

none                5120        0      5120   0% /run/lock

none             1871396      156   1871240   1% /run/shm

none              102400       28    102372   1% /run/user

/dev/sda2      296696828 58764616 237932212  20% /host

It seems like installed in /dev/loop0 but not showing up in Gparted.

Please help me increase the disk space for Ubuntu 13.04.
Note : I coudn't see any GParted disk partitioner to make use of as observed in other threads.