Motion Path Relative to Mouse Position. URGENT

Ok im using MX 2004 although i do have Flash 9 atm if anyone has an example in that
Anyway, im trying to slow down and speed up an orbit of an mc relative to where the mouse position is.
So basically i need some sort of radial “field” where when the mouse gets close to the outside of the orbit the movie clip stops and when it is farther away the movie clip speeds up.

any questions that would help to answer this please ask

Heres the code for the actual orbit

onClipEvent (load) {
var radius = 20;
var speed = 100;

var xcenter = this._x;

var ycenter = this._y;

var degree = 0;
var radian;
onClipEvent (enterFrame) {
degree += speed;
radian = (degree/180)*Math.PI;
this._x = xcenter+Math.cos(radian)*radius;
this._y = ycenter-Math.sin(radian)*radius;

Thanks in advance for your help