"give me a drink"

On our way to church the past Saturday, as usual we have to stop at the "most confusing junction in town". We saw a frail and rugged lady by the roadside, holding up a cardboard with words of needs. We rolled down the window and signaled to her if she wanted a burger. She walked toward the car with an obvious limp, and thanked us profusely. As she walked away, I was greatly embarrassed with the thought that we've given out of extra.
Would I give her my share? Would I skip a meal so that she will not go hungry? The answer most probably is no and I’m ashamed.