LOL the same thing happend to me, I went to my local candian tire and got a stripped bolt remover kit, it pretty much is a bit with teeth that lock into the stripped bolt. and mine were completly round, I tried to use small vicegrips that seemed to work a bit.
WHAT I WISH I DID was removed the whole TB, it honestly takes like 5 minutes, I thought it would of been a much harder job (removed it a few weeks later to test somthing) I was being lazy and trying to get it off with everything still on there.
Just take off the TB.