Can I amend my 2012 2013 returns? The IRS did an audit this year on those returns and there were errors in them. Can I still amend them?

Perhaps.  The deadline to amend a tax return is the later of :

(1) Three years after the due date of the return.  You are out of luck here, because more than three years have passed since the due dates of 2012 and 2013 returns.

(2) Two years after you paid tax associated with the return.  In other words, if you paid additional tax as a result of the audit in the past two years, you can file an amended return that recovers the additional tax you paid, but nothing more.

I would think, however, that if the IRS audited you and you agreed to the audit results, there is nothing further to do at this point.  If you have already received a 'Notice of Deficiency', a 3219A letter, it is too late to amend a return.  You can only file a petition with the US Tax Court, within 90 days of the date of the Notice of Deficiency.