Hmm... your success (or lack of success) at NL200 compared to NL100 can be attributed to one of two things. The difference in skill between the two levels or just variance. 7k hands really isn't that significant in determining your win rate at any given level. Truthfully, it's probably a combonation of the two.

If I was in your situation, I would continue playing NL100. It always amazes me how quickly people like jumping up to the next level. But if you can't beat the game, you are only costing yourself money. I would just continue to make money while learning the game at NL100 until you are ready to make the jump. It should be at a time when you know you are a better player and you are financially/emotionally prepared to drop a few buyins at the higher level.