To Froth or Not to Froth?

Having a hard time deciding if I want to bring the bakery into full-scale coffee shop territory... I've determined that it will cost about an extra $6,000 to fully outfit the place with a small espresso machine, bean grinder, extra dairy cooler, and all the other accessories demanded of a coffee joint. Is it worth the potential extra sales to spend that much more up front? Will it bring in extra sales or just sit in the corner and get dusty? Is it something I should plan for a future expansion instead? So many questions....