It's all been done and said before, here is one thread for example: Stoker Boiler w/ H2O to Air Heat Exchanger for FHA
Information doesn't have to be specific to the model boiler you are talking about, search the forum and see what comes up for heat exchanger or air handler.
Are you planning the install yourself? If so you can talk with an A coil manufacturer (search the web) and get the information on size and cost. If not your plumber can help.
Hope this helps.