After you file

I have read through this whole thread because today I got my bank interest for $100.00 I did not report, because when I checked there was none.  I filed on 1/27 and today is 2/1.  It is currently accepted and in processing.  Being a 50/50 chance they don't catch it and I get my return as is, I will do an amendment. How do I figure out the taxes owed on it to send a check with it?  I had turbo tax do my taxes to figure these things out, I have no idea what to owe on it like the original question.

Can I do the amendment through turbo tax and it tell me?  I feel kind of stuck right now and wanna be prepared.  In all reality I need my return asap because I am broke and since it was accepted does that mean they will catch it?

Thanks!