I would like to break my lease 5 months early. The landlord said I could but is making me find a replacement to sign a new 12 month lease. I found someone who would be willing to finish the 5 months but does not want a 12 month lease. Do I have to find someone to sign 12 month lease?

Also, I have problems with mold growing on the walls and there are no screens in the windows. Are these reason enough for me to be able to break the lease? If so what is the process for going about that?