How do I fix a brush?

Got up this morning only to find that my makeup brush was broken. The bristles were strange, and the hard part of the stick was in half. My sister probably broke my cosmetic masterpieces, but is there any way to glue it back together? I spent so much money on my makeup brushes, I dont want to spend any more. :( My best friend, who is a makeup artist at MAC told me she may just get me a free one.