If you have concrete proof that the agent knew of the defects but conspired with the seller to hide those defects, you might have an claim against the agent's insurance. All real estate agents carry 'errors and omissions' insurance.
If you have proof that the homeowner failed to disclose known defects and you signed an arbitration agreement, you could take your case to arbitration. You would not need an attorney and the fee for filing arbitration should be less than $500.00. If you AND the buyer didn't sign arbitration, then you would have to go the court route.
Follow the link below for Milwaukee Legal Aide.