Have you considered writing her a letter to tell her how you feel? You mentioned earlier that when you talk, she tends to back you into a corner, so if you wrote a letter, there would be no chance for her to interrupt you or change the subject. It's also a good way to let her know how serious you are about improving things.
You know, the thought of a letter has crossed my mind.... I've always thought it was a chicken's way, but maybe it isn't. I'd get to make sure I said what I needed to say, and she'd get plenty of time to think about her response. I will have to think about that. I might change my mind!
I like the idea of a letter- changing the mode of communication might help, so that or the phone maybe?! You both used to write letters when you were courting though didn't you?