Returns filed for wrong ay

Hi,

While filing my I.T Return for A.Y 2011-12, I wrongly filed Return in Form for A.Y 2010-11. Later I received a intimation letter u/s 143(1) demanding an amount to be payable without taking into account my TDS creditable for the current year.
 

Also I had no income for AY2010-11 as I was studying.

What is the procedure that I should follow to handle this situation.

Kindly reply ASAP as this is critical.