Problem with an Arduino Leonardo and motor

Hello guys. I am using an Arduino Leonardo and an L293D shield and 2 motors 3-6v each. I want to make a little car/robot and i am using an bluetooth 4.0 BLE CC2540 i think thats is ok. The code is working I think when i am in serial monitor i get a feedback from the forward function but the motors are not spinning or anithing and I think the wires are good connected. I am using 4AA bateries in series each 1.2v and I think that is the problem.
I am new in this and I need some feedback from you guys.
This is my code.

#include <AFMotor.h>
//initial motors pin
AF_DCMotor motor1(1, MOTOR12_1KHZ); 
AF_DCMotor motor2(2, MOTOR12_1KHZ); 
char data = 0;

char command; 

void setup() 
{       
  Serial.begin(9600);  //Set the baud rate to your Bluetooth module.
   Serial.println("Motor test !");
}

void loop()
{
   if(Serial.available() > 0)  
   {
      data = Serial.read(); 
      //Serial.println(data);
      Stop();

      switch(data){
     case 'a':
        forward();
        break;
     case 'c':
        back();
        break;
     case 'b':
        right();
        break;
      case 'd':
        left();
        break;
     }
   }
 }

void forward()
{
  Serial.println("Going Forward...");
  motor1.setSpeed(255); //Define maximum velocity
  motor1.run(FORWARD); //rotate the motor clockwise
  motor2.setSpeed(255); //Define maximum velocity
  motor2.run(FORWARD); //rotate the motor clockwise

}

void back()
{
  motor1.setSpeed(255); //Define maximum velocity
  motor1.run(BACKWARD); //rotate the motor anti-clockwise
  motor2.setSpeed(255); //Define maximum velocity
  motor2.run(BACKWARD); //rotate the motor anti-clockwise

}

void left()
{
  motor1.setSpeed(255); //Define maximum velocity
  motor1.run(BACKWARD); //rotate the motor anti-clockwise
  motor2.setSpeed(255); //Define maximum velocity
  motor2.run(FORWARD); //rotate the motor anti-clockwise

}

void right()
{
  motor1.setSpeed(255); //Define maximum velocity
  motor1.run(FORWARD); //rotate the motor clockwise
  motor2.setSpeed(255); //Define maximum velocity
  motor2.run(BACKWARD); //rotate the motor clockwise

} 

void Stop()
{
  motor1.setSpeed(0); //Define minimum velocity
  motor1.run(RELEASE); //stop the motor when release the button
  motor2.setSpeed(0); //Define minimum velocity
  motor2.run(RELEASE); //rotate the motor clockwise

}

What motors? They may require more current that a 293D can provide from 4AA's