Hi,you can try the following code:
int Power=9;//addition code
unsigned char buffer[64]; // buffer array for data recieve over serial port
int count=0; // counter for buffer array
void setup()
{ GPRS.begin(19200); // the GPRS baud rate
Serial.begin(19200); // the Serial port of Arduino baud rate.
pinMode(Power,OUTPUT);//addition code
digitalWrite(Power,HIGH);//addition code