Spelling Mistake in Surname

In my passport the surname is my father's name and has got a spelling mistake (an 'i' extra). However, my father's name is correct in the last page of passport. The passport was issued in chennai 5 years back. Im required to travel abroad (first time going to use the passport) next month. What are the ways to rectify this mistake at the earliest (iam not sure whether it was mistake from my end or at passport office end. either way i require a solution,even at the cost of paying penalty at the earliest.
Please solve my query.

Where are you travelling to and what is your nationality? Some countries are more strict than others. I was on a flight yesterday and someone was travelling whose passport EXPIRED 10 months ago yet they let him travel.

Why not just travel under the name as it appears in your passport?

Are you traveling as a tourist? Or a student/work etc? If it is the latter, get the passport corrected in India. If not, all your legal documents abroad will reflect the incorrect name.

Hi
I want to know what is the procedure to change the name in a passport that is expired 2 years back. I have to apply a new passport and the agent says that the old passport's name has to be corrected first.Please help.URGENT!!

Check here:

http://passport.gov.in

And here specifically: http://passport.gov.in/cpv/faq.htm