1- First of all know that Allah will compensate you for your act of goodness towards her. Try not to bee too concerned with how others look at this situation. What’s important is how Allah looks at such situations.
2- Be open with her. In a respectful way, telling her that what you are doing is putting me in a difficult spot and it’s making me look bad. And politely ask her not to do that anymore. So you just have to be open and clear with her. And remind her that she is your friend and you would always be willing to help her, but she cannot take advantage of you.