Substring Respond from GPRS Arduino AT Command

Question

I'm using Module sim 900 (V.1), When I write "AT+CCLK?" there have a respond is ; "2014/04/11 ; 07:02:08 +28" and then I just want to take "07:02:28" only for write this to sd card.. Anyone here can help me take these one ?

void loop() {
        Serial.println("Loop Starts");
        delay(5000);
        gsm.SimpleWriteln("AT");
        delay(5000);
        gsm.WhileSimpleRead();
        gsm.SimpleWriteln("AT+CSQ");
        delay(5000);
        gsm.WhileSimpleRead();
        gsm.SimpleWriteln("AT+CLTS=1");
        delay(5000);
        gsm.WhileSimpleRead();
        gsm.SimpleWriteln("AT+CCLK?");
        delay(5000);
        gsm.WhileSimpleRead();
        gsm.SimpleWriteln("AT+CREG?");
        delay(5000);
        gsm.WhileSimpleRead();
}