Entering And Exiting Car

I know this question is asked a lot but I can't figure it out. I have a car with this script:

 var FrontLeftWheel : WheelCollider;
 var FrontRightWheel : WheelCollider;
 var GearRatio : float[];
 var CurrentGear : int = 0;
 var EngineTorque : float = 230.0;
 var MaxEngineRPM : float = 3000.0;
 var MinEngineRPM : float = 1000.0;
 private var EngineRPM : float = 0.0;
 
 

 
 function Start () {
 rigidbody.centerOfMass += Vector3(0, -.75, .5);
     }
 
 function Update () {
     
     EngineRPM = (FrontLeftWheel.rpm + FrontRightWheel.rpm)/2 * GearRatio[CurrentGear];
     ShiftGears();
     audio.pitch = Mathf.Abs(EngineRPM / MaxEngineRPM) + 1.0 ;
     if ( audio.pitch > 2.0 ) {
         audio.pitch = 2.0;
     }
     FrontLeftWheel.motorTorque = EngineTorque / GearRatio[CurrentGear] * Input.GetAxis("Vertical");
     FrontRightWheel.motorTorque = EngineTorque / GearRatio[CurrentGear] * Input.GetAxis("Vertical");
     FrontLeftWheel.steerAngle = 10 * Input.GetAxis("Horizontal");
     FrontRightWheel.steerAngle = 10 * Input.GetAxis("Horizontal");
 }
 
 function ShiftGears() {
     if ( EngineRPM >= MaxEngineRPM ) {
         var AppropriateGear : int = CurrentGear;
         
         for ( var i = 0; i < GearRatio.length; 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;
     }
 }

And It works fine but I want to be able to (When I'm close to my car, press "return" and then I get in my car and I can Drive that; my player disappears. Can Someone please Walk me through on how to do this?

Thanks so much in advance

-Bruno