Yes, there certainly are!
Firstly, if you have a student service thread and each participant has at least 3 posts, you can
claim that and get 25 posts added to your total.
Then, you can thread her on the Quidditch pitch which acts the same as class posts.
There is also the
Beauxbatons spring festival; participation in that will gain you ten more posts (and we haven't announced the prizes for the winners yet) and that is for a single post in one of the races.
Finally, if you join the
Frequent Poster Programme, every time you finish a thread you can claim points, and when you level up there is the opportunity to choose posts as your prize for each level.
With all of those (or even some) I think you've got a pretty good chance of hitting sixth year level in a couple of months

~ Car
ys