Help with non-disclosure

[Sarah Bien]

I am a new investor and less than a month after I purchased my 2 family house the code enforcement officer told me my second unit attic was illegally finished with no permits and is not up to code. Since the attic is no longer a livable area it cuts my 2nd unit square footage nearly in half. 

The code enforcement officer said he mentioned these issues to the sellers and the sellers' agent. He said that the sellers told him they would fix the problem but they waited until I closed on the house and never fixed the issues. I was not informed about the issues until after I closed.

The contractor estimated that it will cost between $12,000 - 15,000 to get the attic up to code. My attorney said I can spend the money to get it to code then try to sue the sellers to get my money back.

I am not attracted to the suing option so I am trying to contact the sellers but they live out of the country. Both the seller and the seller's agent signed the affidavit of title stating "we have always obtained all necessary permits and certificates of occupancy." Is it also the sellers' agent's fault for not disclosing this information even though she knew? Should I try to contact her we well?

Does anyone have any advice?