That's awesome, man. You're doing some seriously heavy work in these kids' lives, probably more than you realize for a few of them. You're working with the right age group, too. When I was in grade school, I was lucky enough to test into a gifted program offered by the district. It allowed me (and the other kids from my school) to be bussed to the gifted school with other kids from other schools for classes once a week. We were able to chose our own course work each semester (4 classes each semester) and pursue our own interests. I took a vertebrate zoology class in 4th grade that was more in depth than any class I took until college. I might have learned a few new facts here and there, but I wasn't challenged until after high school in that area. I also took creative writing classes, classes on Shakespeare, Greek mythology, classical music, physics through legos, aerodynamics through kites, a geology class and some other stuff like that. I think it was the thing that kept me engaged and out of trouble in grade school, and taught me how to study and be ambitious in my projects, which helped in later years of school.
Your program is different, but it provides the same extra push that the gifted school gave me. I still remember many of those teachers' names (I'm 30 now), and the lessons (not just academic) they taught me. I don't doubt that you're going to be the main reason a few of your students go to college an succeed.