I havent played alot of SNGs in the past year, but I used to play them almost exclusively.

My first thought would be that you need to work on your heads up game. Your 1sts are way too low.

Your 1sts and 3rds should be about the same with your 2nd quite a bit lower. Maybe something like

1st...18%
2nd..10%
3rd....18%

When I needed to work on my heads up game, I played alot of heads up SNGs. I dont know which sites have them but I know PokerStars does. Try to get one or 2 of these per day in. They dont take very long at all usually.