Code:

import mx.transitions.Tween;
import mx.transitions.easing.*;
//the variables below will store the clips starting position
circle_mc.myHomeX = circle_mc._x;
circle_mc.myHomeY = circle_mc._y;
circle_mc2.myHomeX = circle_mc2._x;
circle_mc2.myHomeY = circle_mc2._y;
circle_mc.onPress = function() {
startDrag (this, false);
}
circle_mc.onRelease = circle_mc.onReleaseOutside=function () {
stopDrag();
if (eval(this._droptarget) == targetCircle) {
this.onTarget = true;
targetCircle.gotoAndStop(2);
} else {
this.onTarget = false;
targetCircle.gotoAndStop(1);
var moveBack1X:Tween = new Tween(this, "_x", Regular.easeOut, this._x, this.myHomeX, 10, false);
var moveBack1Y:Tween = new Tween(this, "_y", Regular.easeOut, this._y, this.myHomeY, 10, false);
}
var moveDropX:Tween = new Tween(this, "_x", Regular.easeOut, this._x, eval(this._droptarget)._x, 10, false);
var moveDropY:Tween = new Tween(this, "_y", Regular.easeOut, this._y, eval(this._droptarget)._y, 10, false);
}
circle_mc2.onPress = function() {
startDrag(this, false);
};
circle_mc2.onRelease = circle_mc2.onReleaseOutside=function () {
stopDrag();
if (eval(this._droptarget) == targetCircle2) {
this.onTarget = true;
targetCircle2.gotoAndStop(2);
} else {
this.onTarget = false;
targetCircle2.gotoAndStop(1);
var moveBack1X:Tween = new Tween(this, "_x", Regular.easeOut, this._x, this.myHomeX, 10, false);
var moveBack1Y:Tween = new Tween(this, "_y", Regular.easeOut, this._y, this.myHomeY, 10, false);
}
var moveDropX:Tween = new Tween(this, "_x", Regular.easeOut, this._x, eval(this._droptarget)._x, 10, false);
var moveDropY:Tween = new Tween(this, "_y", Regular.easeOut, this._y, eval(this._droptarget)._y, 10, false);
}

Take in mind iv used my MC instance names,