Do they have networking groups in BA like they do here in the US? You can check some of those groups out, take business cards, flyers, etc.. they normally ask you to present a 30 second blurb on who you are, why you are there, etc.. There is a group call IBN - international business networking. unfortunately though they are pretty expensive but could be worth it. The thing with IBN is that you could visit a a chapter to see if you are interested first and if you are visiting in the states I believe you could visit a chapter here as well.
You could also post on Craigslist but instead of posting in the BA CL go to local CL for big cities and advertise on there. Write articles on hubpages ( I think this is a great forum). You can also network with some travel agencies around the world and let them know of your services...maybe they could add your classes to some of their packages.
Would it be possible to advertise with the US consulate there?