Urgent help - itr filing

Hi all,

I filed my IT return for AY 2012-13 one month ago. It had some amount as tax payable but I could pay it then.

Now that I have paid that amount as self assessment tax, how should I inform the IT department about it?

Should I write the Challan number in the ITR V, sign it and attach a copy of challan with it and send?

Please guide, what should I do?

Many thanks

Zishan