How do you completely change your physical mannerisms and body language?

Some people say I have really strange mannerisms and body language. When i saw myself on video one time and looked at my posture, i was like OH...MY...GOD. I looked like the hunchback of notre dame, and when I reached to grab something I moved in a jerky, wobbly motion. I have the mannerisms of a toddler, and I think its the result of the mild asperger syndrome i was diagnosed with at age 9, which means I am neurologically inclined to move like that. Can I change the way I carry myself, and If I Can, How?