Oh, hey! Don't be so hard on yourself. I know you put a lot of time and effort into this quilt and for a good cause. Sometimes things just don't go the way we want them to. You could just let it go the way it is. I'd buy tickets on it. Remember, NO quilt is perfect.
I know it's better than I can do. The most points I've made was in a 12 inch block once, and they were awful!
I really like BellaBoo's idea about fusing a wheel on at each point. A big button could work there, too. If you really don't want to let it go this way, get creative! Sometimes our best work comes out because of a mistake. I remember my art teacher told us this in 6th grade, and I try to remember that.