Mouse follow scroll

Hi,

heres my code. it works great except how can i make it ease into postion when the ymouse is < 10 (the last bit of code does this but without any smoothness)

onClipEvent(enterFrame){

if (((_xmouse > -20 && _xmouse < 140)) && (_ymouse < 190)) {

this._y-=(_root._ymouse+this._y)/7;

}

if (this._ymouse < 10) {this._y = 3}

}

many thanks,
G