Who told you your catalytic converter is out of warranty?

They may be trying to rip you off.

According to my 2004 HCH's manual and warranty information, the emissions control system is warrantied for life.

Try to check your manual regarding the emissions control system. Although yours is a 2003 model, it should be similiar to the 2004 model, and you should not have to pay for anything regarding the catalytic converter.