Comments and a couple of questions

I am watching this for the first time today and haven't read the book. If my questions have been asked before, I apologize for any repeats, but it's hard to read the whole board. First, I love Robin's dramatic roles even more than his comedy, and even though this is an odd movie, I love his performance so much. Favorite scenes, when Helen tells Garp she's pregnant the first time and he draws on her tummy. Then he kisses it and lays his head down. His expression is so sweet and tender! Also when he makes up with Helen after the accident and his daughter is born.

Now on to the questions. Who was the girl who brought the note revealing Helen's affair to the house? That was lost on me. Also, why on earth would Garp make the car "fly" in such bad weather? I know he was angry at Helen, but still. Finally, when Garp was sitting looking at the ocean and the phone rang, he looked like he already knew it was bad news before Helen hollered or told him. Do you think Garp was that connected to his mom? Thanks for your thoughts.