well as the old saying goes "if @ first you dont suceed, try,try again", i wish you all the best of luck with your idea, anything to make life a little more bearable while there is a good thing, i dont really know what else you can do, but the greatest advertisement in this world is word of mouth, maybe on that point, can you make a poster/advert and send it to the people who are playing now, let them show it to others?, i know your a non profit org, but you might be able to add something on the poster that you can charge for, to try and cover your cost of doing this...
im going to sign off for now and look @ your site , see if anything springs to mind, either way , all the best