What can I do to get out of my lease if our landlord refuses to fix a major problem?

My husband and I live in Nashville. We started our lease back in July. Girl in the office had me sign all of the papers before we even got to look at the apartment. I know, should have been a red flag. They told us we would have an upgraded apartment. All they did was put in new carpet and change out the light fixtures to nickel finish ones. Looked as if they didn't clean anything. The kitchen cabinets were peeling (I ended up using super glue to put the top layer back on) and later on we discovered pretty quick that the AC was not working at all. We moved in on Friday and they finally got someone in to fix it on Monday. As winter hit, we found out that we had a really bad draft and the heat wasn't working well. Had maintenance come in and said there was nothing they could do about the draft, that the sliding glass doors are around 30 years old and the owners would not replace them. After she replaced a fuse in the heating unit she attempted to fix the folding doors to the washer/dryer. She said they have limited resources and have to get creative so she ended up putting in two screws to hold a peg up to keep the door in the track. Our apartment is a townhome so they claim that part of the draftiness is due to the open stairwell. I have put up plastic sheeting on both sets of glass doors and put up thermal curtains. Even tried putting down blankets at the bottom. Nothing seems to work. We have the thermostat set on 68 to conserve power but on the really windy days it gets to about 58 downstairs. Even with the thermostat set so low, our power bill was over $200 for a 1 bd 1.5 bath. I noticed our vinyl siding was coming up on the upstairs wall and went to check on it. Come to find out, we only have 1 inch thick styrofoam panels as insulation. When we had a storm a couple of months ago, the rain was beating the glass doors so hard that where the "new" deck was attached upstairs, it started pouring water into the downstairs. Maintenance took a look and just said that it was "sweating". I started looking for more problems and decided to have a look at our "vents" in the bathroom since everyone knows that every bathroom needs to be properly ventilated to the outside. Well our vents are actually just inserts into the wall with a tiny fan to blow air up to the ceiling. Almost forgot to mention that 5 minutes after we had set up the furniture upstairs we noticed that the drawers to our nightstands kept opening so I grabbed a ball and set it on the back of the nightstand and it rolled right off. The entire upstairs is leaning in toward the center of the room. We have petitioned the front office twice about fixing the draft problem but both times they have said there is nothing they can do, that it's just an old building. Maintenance says the same thing and told us that pretty much everyone has the same problems that we do. Is there anything we can do to get out of this mess???