ActionScript 3.0 :: Add A Comma To Dynamic Text Field?

I have this working, but I am looking for a better solution.This bit calculates to total amount and rounds up:

Code:
textTotalVar = Math.round(text1Var * text2Var * text3Var * text4Var);
textTotal.text = textTotalVar + " lb/hr";

This bit toggles the comma if textTotalVar is a thousand or greater.[code]........I would like more space on either side of the comma so it doesn't look crowded. How can I do the below when the total value is five characters, for characters and three or less with a hidden comma?

Code:
textTotal.text = first character of textTotalVar + " , " + last three characters of textTotalVar + " lb/hr";