Update. I talked to the place I got the tires from, and since I got them under special circumstances, they distinctly remember them being all the same size. So I only drove a max of 60 miles on mismatched tires. In happier news I just got my replacement tire in and am going to go get it mounted it tomorrow.
I did notice the smaller tire had some smeared yellow new tire markings, so I am sure the local subaru dealership screwed up something. They offered me $75 because they didn't notice mismatched the tires were mismatched. I took the $75 since I don't think I will get anything better from them. I'm chalking this up to a lesson learned and never taking my car back there again for anything.