I couldn't find a replacement oem button for the toaster, you can go to radioshack and pick up a toggle switch and try that or buy a new toaster. Sorry
I had the same problem, I just added this video to youtube teaching you how to re-connect your battery (this is a very common issue with the nexus 7) http://www.youtube.com/watch?v=X-Hp3Gl-isQ&feature=youtu.be
