Tenants cannot stop a foreclosure. *IF* you leased before the notice of default was filed (unlikely, if you received a notice of sale in your first month), you are entitled to stay for six months or a year under various laws, if you had a lease for that long. You can probably also get a payment for moving out after it sells.
Considering that the property is in foreclosure, your landlord is not likely to fix the air-conditioner. You should look for another place because this one is not habitable.