Error while mounting partition with Live CD

While booting my system, It is going into initramfs prompt and it is giving some error. Before taking any further steps, I planned to take a backup my data from hard disk. So, I bootted the system with Live CD.

When, I trying to mount the partition, I am getting this error.

root@ubuntu:~# mount dev/sda1 /mnt/
mount: wrong fs type, bad option, bad superblock on /dev/sda1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

The following errors are logged in syslog:

Jun 21 08:10:34 ubuntu kernel: [  739.053669] ata3.01: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
Jun 21 08:10:34 ubuntu kernel: [  739.053675] ata3.01: BMDMA stat 0x64
Jun 21 08:10:34 ubuntu kernel: [  739.053680] ata3.01: failed command: READ DMA EXT
Jun 21 08:10:34 ubuntu kernel: [  739.053688] ata3.01: cmd 25/00:f0:a0:f5:6f/00:00:18:00:00/f0 tag 0 dma 122880 in
Jun 21 08:10:34 ubuntu kernel: [  739.053690]          res 51/40:00:af:f5:6f/40:00:18:00:00/10 Emask 0x9 (media error)
Jun 21 08:10:34 ubuntu kernel: [  739.053694] ata3.01: status: { DRDY ERR }
Jun 21 08:10:34 ubuntu kernel: [  739.053697] ata3.01: error: { UNC }
Jun 21 08:10:34 ubuntu kernel: [  739.164130] ata3.00: configured for UDMA/100
Jun 21 08:10:34 ubuntu kernel: [  739.196323] ata3.01: configured for UDMA/133
Jun 21 08:10:34 ubuntu kernel: [  739.196345] sd 2:0:1:0: [sda] Unhandled sense code
Jun 21 08:10:34 ubuntu kernel: [  739.196348] sd 2:0:1:0: [sda]  Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
Jun 21 08:10:34 ubuntu kernel: [  739.196353] sd 2:0:1:0: [sda]  Sense Key : Medium Error [current] [descriptor]
Jun 21 08:10:34 ubuntu kernel: [  739.196359] Descriptor sense data with sense descriptors (in hex):
Jun 21 08:10:34 ubuntu kernel: [  739.196362]         72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00
Jun 21 08:10:34 ubuntu kernel: [  739.196376]         18 6f f5 af
Jun 21 08:10:34 ubuntu kernel: [  739.196382] sd 2:0:1:0: [sda]  Add. Sense: Unrecovered read error - auto reallocate failed
Jun 21 08:10:34 ubuntu kernel: [  739.196389] sd 2:0:1:0: [sda] CDB: Read(10): 28 00 18 6f f5 a0 00 00 f0 00
Jun 21 08:10:34 ubuntu kernel: [  739.196403] end_request: I/O error, dev sda, sector 409990575
Jun 21 08:10:34 ubuntu kernel: [  739.196418] JBD: Failed to read block at offset 31637
Jun 21 08:10:34 ubuntu kernel: [  739.196430] ata3: EH complete
Jun 21 08:10:34 ubuntu kernel: [  739.197001] JBD: recovery failed
Jun 21 08:10:34 ubuntu kernel: [  739.197004] EXT3-fs (sda1): error loading journal

How to take safe backup of my data? and How to fix this issue?