Urgent suggestions needed

[Question please]

Hello

My name on the passport was FNU, XX YY- which is how it came on the I-797 (H1 approval).

I got my passport corrected to reflect my correct name- XX YY.

How can I get the name on the I-797 fixed? How much time does it usually take and how much amount does it take to get the name fixed?

(P.S.- The new passport has a new passport number).

Any suggestions will be highly appreciated.

Thanks

tensed! =(