Bitten by a dog - will the police prosecute/can I sue?

Yesterday I was at a park with my toddler in an enclosed (by fence) area clearly marked as "no dogs". Some woman threw a a stick about two metres from my child and opened the gat so her dog could enter and get it.

The child was frightened.

I quickly placed myself between to protect him and the dog attacked and bit me.

She didn't even apologise, saying the dog likes to play with children. I pointed out that for my child it's not her decision, and that the rules are no dogs in there (and all dogs on leashes).

I called the police but they "were too busy". Is it worth going into the police station and kicking up a fuss? I have a good description and I know roughly where she lives.

I'm out two hours and a doctor's bill of about 50 eur.