car controls gui

I have trouble combining two scripts for iPhone controls. I have script for GUI texture that represents gas pedal, and a script for vehicle control. Realy don't know what to do... I would appreciate any help. Thanks!!!

This is my Gui script

function Update() {

if(Input.touchCount > 0){ var touch : Touch = Input.touches[0];

 if(touch.phase == TouchPhase.Began && guiTexture.HitTest(touch.position) )

 {
     Something goes here...
 }

}

}

And this is the vehicle script

var FrontLeftWheel : WheelCollider;

var FrontRightWheel : WheelCollider;

var GearRatio : float[];

var CurrentGear : int = 0;

var EngineTorque : float = 600.0;

var MaxEngineRPM : float = 3000.0;

var MinEngineRPM : float = 1000.0;

private var EngineRPM : float = 0.0;

function Start () {

rigidbody.centerOfMass.y = -2;

}

function Update () {

rigidbody.drag = rigidbody.velocity.magnitude / 200;

EngineRPM = (FrontLeftWheel.rpm + FrontRightWheel.rpm) /2 * GearRatio[CurrentGear];

ShiftGears();

    FrontLeftWheel.motorTorque = EngineTorque / GearRatio[CurrentGear] * Input.GetAxis ("Vertical");
    FrontRightWheel.motorTorque = EngineTorque / GearRatio[CurrentGear] * Input.GetAxis ("Vertical");

function ShiftGears() {

if ( EngineRPM >= MaxEngineRPM ) { var AppropriateGear : int = CurrentGear;

 for ( var i = 0; i < GearRatio.length - 1; i ++ ) {
     if ( FrontLeftWheel.rpm * GearRatio[i] < MaxEngineRPM ) {
         AppropriateGear = i;
         break;
     }
 }

 CurrentGear = AppropriateGear;

}

if ( EngineRPM <= MinEngineRPM ) { AppropriateGear = CurrentGear;

 for ( var j = GearRatio.length-1; j >= 0; j -- ) {
     if ( FrontLeftWheel.rpm * GearRatio[j] > MinEngineRPM ) {
         AppropriateGear = j;
         break;
     }
 }

 CurrentGear = AppropriateGear;

}

}