Help with ActionScript and a count down timer

HI I have created a movie Clip for a count down timer. The Count down timer movie clip has two layers with only one fame each. The first layer is the actions, the second holds a text field with a variable name timer_txt and this is where the count down timer results are shown.

I have managed to get the timer to go down to zero, however, i need it continue into negative numbers. What I thought was to have a booleen value which will change the timer from subtracting to adding 1. But this does not work… can you please help me with this.

The following is the code in the actions layer on frame one :

 
//initial variables
var timing:Boolean = false;
var paused:Boolean = false;
var remaining:Number;
var elapsedTime:Number;
var elapsedHours:Number;
var elapsedM:Number;
var elapsedS:Number;
var elapsedH:Number;
var startTime:Number;
var remaining:Number;
var hours:String;
var minutes:String;
var seconds:String;
var hundredths:String;
var timeOut:String;
startTime = getTimer();
timing = true;
var timeSec:Number;
var timeSecStr:String;
var timeMin:Number;
var timeMinStr:String;
timeSec = 60;
timeMin = 10;
 
//_root.createEmptyMovieClip("countDown", 10);
//cCenterX = Stage.width/2;
//cCenterY = Stage.height/2;
//_root.countDown.createTextField("myTextField", 1, cCenterX, cCenterY, 30, 20);
//_root.countDown.myTextField.background = true;
//_root.countDown.myTextField.autoSize = "center";
//_root.countDown.myTextField.border = true;
//_root.countDown.myTextField.backgroundColor = 0x00FFCC;
count = 3;
minCount = 9;
timeOut = "F";
myCountDown = function () {
if (this.timeOut == "F") {
count--;
if (count == 0){
var myTextFormat = new TextFormat();
myTextFormat.color = 0xff0000; 
this.timer_txt.setNewTextFormat(myTextFormat);
this.timeOut = "T";
}
 
}
else if (this.timeOut == "T"){
count++;
}
 
}
countInterval = setInterval(myCountDown, 1000);
this.onEnterFrame = function() {
 
elapsedH = Math.floor(count/60);
elapsedM = count-(elapsedH*60);
 
if (timeOut = true){
timer_txt = "-";
}
else if (timeOut = false){
timer_txt = "";
}
 
 
if (elapsedH < 10){
timer_txt = "0" + elapsedH;
}else
{
timer_txt = elapsedH; 
}
 
if (elapsedM < 10){
timer_txt += ":0" + elapsedM;
}else
{
timer_txt += ":" + elapsedM; 
}
//timer_txt = mincount + ":" + count;
//if (count == 0) {
//
//clearInterval(countInterval);
//timer_txt = "00:00";
 
//}
}
 

Please note that there are some redundant variables in there, and while I have been trying to solve this the code has become messy.