What would I need to add a coffee bar to my art gallery. This will not be a full coffee shop. I just want to add another service to my gallery.

There are several coffee service companies in large market areas that supply equipment. Also if you would like to offer cap and espresso than a good cappicino machine costs $5000 and would need an operator.

You could offer a few coffee gifts such as subscriptions to those coffee companies that send coffee directly to your door. Here is a link that has some interesting coffee facts. Did you know people use to eat the coffee beans?
http://www.ochashomeshop.com/coffee.html