Your text field should be an input text field. Let's say its instance name is hsNum. You put it on stage like any display object. Now you can change its text like this:
hsNum.text = "thistextrighthere"
or hsNum.text = " "
or hsNum.text = thisstring
, where you've already defined thisstring.
So, the relevant bit of your code might be:
hsNum.text = String(new_hs_num);
Remember to 'embed' the appropriate characters for your input text field.