Where do I file a claim against my slumlord (landlord)?

We live on a commercial and residential zoned property that has a detached garage and office and the house. When we came to look at the house (when it was for rent still) before we even signed the agreement the landlord stated that in the summer (moved in during March 2005) he was going to repair the garage and other repairs that were in great need of some attention. As of today, the landlord has done nothing but put spouting on the side of the house. The garage is so bad that if the zoning department seen the garage they would condem it. The roof is about to cave in and the floor of the loft (attic-garage) is falling through and pieces of wood are missing. The landlords wife just ped away which I feel bad for him but still he owns this place and he should care for it. We have been faithful with paying our rent and everything. Where can I file a claim against my landlord to hopefully motivate him?