How to get the ITRV of last year i.e 2010-2011

We have filled our return last year, but not able to sent the ITRV to income tax dept. Now we have lost the ITRV and we are getting mails for submittng the ITRV.

"ITRV NOT RECIEVED, PLEASE FURNISH YOUR ITR V to CPC URGENTLY. For ITR ack number *****" 

What should be the next step?

How we can get ITRV (we have only ITR ack number)?

Please let me know ASAP, as the last date is very close.