data loss - Lost partition while installing Ubuntu

I am new to Ubuntu.

Earlier I was using window 7 and had 2 drives. A few minutes back I installed Ubuntu 13.10 on my laptop. While installing, I selected the "replace Windows 7" option, and now I can see only 1 drive. This is output of fdisk.

vishal@Ghost-PC:~$ sudo fdisk -lu

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0002ad36

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *        2048   968800255   484399104   83  Linux
/dev/sda2       968802302   976771071     3984385    5  Extended
/dev/sda5       968802304   976771071     3984384   82  Linux swap / Solaris

I think I lost my other drive. Please confirm how to recover that drive, because the drive is very important.