I can't speak for your program's requirements, but I know how daunting creating the proposal can be. My suggestion is to decide what author(s) or text(s) you plan to work with, then find a direction (what critical lens you want to use, a problem you want to work out, etc.). Our proposals were due a year before graduation, so they didn't have to be terribly specific as long as you had a sense of what you wanted to write about. We were also required to include a reading list of texts, scholarly articles, etc. that we intended to use for the thesis. My proposal was maybe five pages by the time I was finished, and my thesis director asked that I be very specific (compared to what other directors wanted). I hope some of that is useful for you. Best of luck!