Look,
If You are a Salaried Employee You should ask for Form 16
If your income is other than salary like consultant etc you should ask for Form 16A
So much for Basics,
Now, You seems to File your Returns for FY 2012-2013 for which the last date will be 31-07-2013,
Now its a duty of your employer to Issue you Form 16/16A's before the a stipulated month (much before your last date to file returns)
If you dont receive your Form raise the issue with concerned Income Tax Offcer...
and if you are a salaries employee you need to file ITR 1 where you have to fill the tds deducted details and nothing more so for this you might need Form 26as
and if you are non salaried and filing your return as Professional you file ITR 4 where you need Form 16A which has certificate number Mentioned which you too have to mention in your return, where as form 16 dosnt have any certificate number...
so i guess you can just fill the tds details in your return if you even dont have form 16 based on your form 26 AS
Cheers!!