Creating Mortgage Calculator

http://www.portraitofanger.com/flash/mortgage_calc_as2.fla

Here is the flash file, I feel as if I am almost there, but the calculation doesn't add up.

submit_btn.onRelease = function()
{
     var p:Number = parseInt(amount.text);
     var r:Number = parseInt(percentage.text) / 100 / 12;
     var n:Number = parseInt(years.text) * 12;
   
     var a:Number = ((p * r) * Math.pow(1 + r, n)) / (Math.pow(1 + r, n) - 1);

     results.text = Math.round(a*100)/100;
}