Renting with option to buy what are my rights?

I am renting a home in pennsylvania that I had planned on purchasing in march however upon moving in we have found major problems with the house. The sewer drains in the basement stays flooded. where the landlord has drywalled over the chimney, the paint has bubbled and has became molded. The upstairs bathroom leaks water into my livingroom downstairs. The support beams(wood) in the basement are molded. We have made him very much aware of the problems and he states that the house comes "as is" and that he is not going to pay for the repairs. I have a "Renting with option to purchase" lease and in the lease it states that I am responsible for any repairs that is caused by my neglagence. I know that in the state of PA that any major problems such as electrical, plumbing, lead or mold has to be disclosed to the potential buyers and he failed to so. Is there any thing I can do legally do to make him pay for the repairs?