[Bridget]

I am having several problems with my 95 Camaro. I have asked a few people for their advice and I get something different each time. I'm new to the area and am skeptical about going to ANY garage. If I had the heads up, I may be able to specify what help I need before I get taken to the cleaners (again).
First, my AC is coming out of my defrost and floorboard vents, it should be coming out of my dash vents. Before this happened (for a short time) when I accelerated and the AC was on, I would lose my air until I reached a steady speed or let off the gas, then my air would return. Now it's just blowing through the defrost and floorboard vents.
Second, my Check Engine light is on and has been for approx 2 years. The codes showed it to be the EGR. I had a used one put in but the light stayed on. They cleaned my ports, but the light is still on. The light comes on after I have been on the road for a few minutes and usually comes on when I decrease from a steady speed.
Third, my driver door is sagging. Several opinions (one being that I will need welding) have been given. My door flung backwards in a high wind and has sagged since. If opened all the way, it will catch mid way closed, then catch again right before I shut it. With a little lifting it will close.
Fourth, When I climb a steep incline my car boggs down and makes a clunk once I have reached the top. I had a used rear end put in a couple years ago.
Sounds like the best thing to do is sell it, but I love my car. Can someone please give me a place to start?