Chetan, since that post is over six months old and the OP only has a total of 2 posts on this forum, I think it's safe to say that they won't be returning here.
In regards to recovering deleted items such as this, you need to check your Recycle Bin on your PC or Trash or your Mac. It is for situations like these that you should NEVER setup these receptacles to delete immediately but leave them to be deleted at a later point manually which will give you some time to review the items and determine if you really mean for them to be eliminated from your computer. Also, it is good practice in general to backup all of the contents of your computer to an external harddrive monthly, if you can. I, for one, make sure I not only specifically make a back up of the Camera Roll (I just did it 2 days ago), I also make back ups of my iPhone Back Up files, iTunes Music Library, iTunes Library XML file, Microsoft Outlook Contacts (which I sync with the iPhone), and anything I create, edit or update as a file on my computer. In this way you will never be wonting when it comes to trying to find ways to rescue files that have been deleted for any reason. File recovery is expensive, time consuming and can be inaccurate at best, especially when a good percentage of the files you recover can be corrupted and unusable.