I agree with HTG, you need to focus on making a much bigger arena. Look at any top team in D3 and you'll see arenas that are twice your size and sometimes bigger. The game engine rewards bigger arenas with lower prices moreso than small arenas with high prices.
You're not going to promote this year (or more to the point, you don't want to promote with such a small arena) Assuming that you can afford it, I would look at building bleachers for now and raise your other ticket prices.