Sliding menu problems

1

Ok im have a small problem with my sliding menu. It all works good but when you roll over it I want it to stop moving at a certin spot. I know I dont make sence but when you role over the movie clip it roles up and then rolls back down. Can some one help me please?

Here is my code

Movie Clip
onClipEvent (load) { 
yMove = _y; 
easeSpeed = 5; 
_y += (yMove-_y)/easeSpeed;

} 
onClipEvent (enterFrame) { 
 _y = _y+(95-_y)/6;
} 



Actions Layer
a.onRollOver = function() {
	easeSpeed = 5;  
	yMove = button_1._y; 
	this._y += (yMove1-this._y)/easeSpeed; 
};

and a is the movie clips name