Passanger in car accident

In August  i was a passenger in a car accident. I was taken by ambulance to Rennes hospital but did not have my carte vitel with me at the time. The driver of the car , who had been doing a dangerous uturn, at the time , said she would cover the medical cost on her car insurance.
I no longer have any thing to do with her for personal reasons.
Today i recieved a red demand for payment of medical treatment. The address of the driver ,where i had been lodging at the time(now a former friend), had been covered by a glued on scrap of paper and my new adress hand written over the top. The envelope had been opened and resealed. There must have been a number of previous bills prior to this one. Where do i stand legally on payment of this bill , which i really can't afford , and feel should have been covered by the person driving. Advice please.