Suggestions for coding? timeline animations for navbar

I used After Effects to make pngs to use in a timeline in flash. Here it is to look at:

When you mouse over the navigation bar I want the windows to move in reverse order fluidly. (You’ll get what I mean if you look at it.) Right now I’m using this code for in the timeline for the buttons.

navbar_mc.addEventListener(MouseEvent.MOUSE_OVER, navOver);

function navOver(event:MouseEvent):void{
    navbar_mc.setChildIndex( as MovieClip, 1);

Does anyone have any suggestions on how I should go about doing this?