Hi, As your immediate problem seems to be tearing your calf muscle due to running, I doubt this is connected directly with your cerebral palsy. However, the effects of cp can mean that calf muscles are very tight and this would have been the case as a child. Have you ever had any treatment like surgery or Botox on your calf muscles? If not, it may be worth asking for a referral to a neurologist otherwise your orthopaedic doctor should be able to treat your needs.
Don't know of any specialists in the US but you could try asking the United CP Association http://ucp.org/ as they are the main organisation in the US for people with cerebral palsy.