I have no suggestions for a replacement bumper sticker, but if you still have remnants of the old sticker, use a blow dryer. Put the setting on high heat and blow toward the sticker. This causes the glue to heat and soften and make it easier to remove.
Congrats on leaving the RATS. Commiseration at becoming a pubbie.
Thanks for the advice about removing the old bumper sticker. Freepers are a great resource for how to get something done.