The association bonus does not count...now. You could say there was a bit of an oversight initially and it was counted. But since you asked this question, we are now excluding the association bonus, so thanks for asking this because we wouldn't want to give out too many hats.
Otherwise you could just sign-up to 3 new sites, get the association bonus in each of them, and you'll only need 50 more rep on each of those sites to get the hat. That would make the hat 3 times less difficult to obtain.