I too have GeorgetownXL, mines a 2008 and I had the same problem. It took a while to resolve, but I did. I found the manufactures name on a tag stuck to the bottom of my sink (Duo-Form Plastics). I did a little web searching and made a call. The person you need to talk to is Jennifer Pitcher, Customer Service Manager, at (269-228-5047). She emailed me the drawings for the sink and I confirmed that it was the right sink and called her back and placed an order ($35.00 + shipping). The drawing shows a part number of 151824121 which is white. You want a 151824154 which is Clay Breccia (two tone brown).
Hope this helps