Looks like you got alot of advice on the forehand and not so much on the backhand, so I'll give you advice in that area.
You have no topspin on your backhand, and your definitley going to want that if your going to want a consistent backhand. The reason for your lack of topspin is that your not letting the racket drop below the ball. You are swinging straight THROUGH the ball instead of swinging UP and through the ball, which is the motion that creates topspin. Also make sure to bend your knees in order to get under the ball. See this picture and notice Federer's racket well beneath the ball. He does in order to create topspin. Right now you have a very risky backhand, as it is really hard to hit hard and flat consistently
Also, as soon as you recognize your going to hit a backhand set up as soon as you possibly can. A good 1hbh needs very good footwork, and the more time you have to set up the better. Run to the ball, set your feet, and swing with a high to low motion to create topspin.
For your slice backhand, I suggest you start hitting through the ball more so it doesn't float/sit up as much. Overall though, lack of topspin on your backhand and the lazy footwork is your problem. I think you told me you've been running, so keep that up! Work on your speed, it will help I guarantee it.
Good luck though, your improving a good rate so keep it up