Very frustrated puzzler

Here's my latest "finished" puzzle. It was a really hard one, which is why the two missing pieces are so effing frustrating!

I have no idea what could've happened to them. Did Rusty eat them off the floor? Did they fall into the trash? Were they never in the box? BOO! I really wanted to frame this one.

I might try to figure out a creative way to fill in the two small spaces, but right now I'm too darn mad.