<div id="container">

    <div id="middle">Centered to middle</div>

    <div id="right">I want to to be to the right</div>

</div>

#container {
    position: relative;
    width: 100%;
}

#middle {
    margin: 0 auto;
    position: relative;
    width: 100%;
    max-width:150px;
    height:300px;
}

#right {
    max-width:150px;
    width:100%;
}