i feed aislynn breastmilk from a bottle about 60% of the time now, (i'm starting to admit that she never really ate enough when she nurses, and gives up before she's full...) and I am pumping to keep the supply up. i take a supplement to help and try to pump every 2 hours even though she eats every 3-4 hours. Right now, I have about 35 ounces in the freezer an 8 ounces in the fridge, and it slowly increases.
moral of this story is it can be done!