First, I'm wondering how long it takes you to swim 200m backstroke. A little over an hour for 2000m would mean that you're averaging a little over 6 minutes per 200m, but can you swim faster than that if 200m is the total distance you're doing?
The video you shot is a bit short and is taken from an unusual angle. When we do underwater videos, we normally do it from the side, which makes it very easy to see whether a swimmer is balanced, etc. But it looks to me like your hips are a bit lower than your shoulders, and it looks like your kick is a bit wider than it should be.
I'm also seeing an asymmetry in your arm stroke: The first part of each stroke should be an "arm wrestler" type of movement, while during the second part you should be throwing water toward your feet. But it looks like your left arm is staying straight at the elbow throughout your stroke and only your right arm is bending at the elbow (i.e., the "arm wrestler" movement).
I'm also wondering whether you have tried using fist gloves while practicing backstroke (http://www.totalimmersion.net/store/...l#.Vz88aJDmp9A
). They can help you learn to grip the water better.