何が言いたいのかよくわからんが、

private Point prePoint;
public void mouseDragged(MouseEvent me){
Point nowPoint = me.getPoint();
this.setX(this.getX() + (nowPoint.x - pre.x));
this.setY(this.getY() + (nowPoint.y - pre.y));
pre = me.getPoint();
}

こんな雰囲気でいけると思うんだが