Gas station cappuccino isn't actually cappuccino.
if you go to a coffee house and order one-it won't be the same thing. Gas station varieties are pretty much hot cocoa with a dash of coffee thrown in for good measure!
I would recommend that you try regular coffee with a little flavored creamer (measured out) for 50 calories or under, or to go for what I do-which is the foo-foo flavored coffee beans (the beans are flavored-no sweetener though) and either drink it black if you can-or add a dash of Splenda or Equal.
It isn't going to be the thick, syrupy thing like you get at a gas station though. If you want to slowly wean yourself from the sugary gas station thing-fill your cup with half of the cappuccino and half with regular coffee (cuts calories in half) and then slowly up the coffee and reduce the cappuccino over time.
In a real coffee shop you can get a latte with nonfat milk (a small would be around 80 calories) and add a dash of Splenda if you still need something creamy-milky.