convert api response to json......

i get response from api like below.....
response : %5B%7B%22event%22%3A%22Execute%22%2C%22ts%22%3A1381398344%2C%22msg%22%3A%7B%22my_msg%22%3A%22Received%3A+from+Mitesh+%28Hello Every body+%5B

now my class is like below..
public class MyEvent { [JsonProperty(PropertyName = "ts")] public string ts{ get; set; }
[JsonProperty(PropertyName = "event")] public string event{ get; set; }
[JsonProperty(PropertyName = "msg")] public Message Msg { get; set; } }
public class Message { [JsonProperty(PropertyName = "my_msg")] public string RawMessage { get; set; }
}



Now i want to conveert response in belew format

response="event":"Execute", "ts":"", "msg":{"my_msg":"Received from Mitesh Hello Every body ...