On Sunday 22nd August, she was approached by a man in a car on Molsey Road, who got out and stole her phone.
He then pushed her to the floor and stamped on her head.
She was taken to hospital where she was treated for minor injuries.
The suspect is described as a man in his early forties, bald and around 5ft 8”.
Police are asking witnesses or anyone with information to contact them on 101, or Crimestoppers to remain anonymous.