I don't know what a proper response is but here are five potential responses. Feel free to use them next time this happens.
1. Oh yeah? You remind me of every lame assh*le I see here.
2. Oh, she must be an amazing woman. I feel bad for her.
3. That's really funny I was about to mention the same thing.
4. Oh cool, we should all go out sometime and do meth on a high school rooftop. Idiot.
5. But unlike her I already know you are total turd.