Help with Name correction in Visa

[imchandan]

Hello,
I have just got the Visa as:
Given Names: FNU
Last name: CHANDAN KUMAR
because of Last name blank in my passport.

I have 3 months time in india before i travel. Can anyone please help me get it corrected ? I know i can resubmit online application for Passport correction but do they keep older passport with them ?
And how to get Visa corrected ?

Thanks,
Chandan