You should be able to position the child div by using absolute positioning. Set the parent div to relative position, then child to absolute and bottom:0; You will then need to adjust the vertical align of the <td>
elements if you want the parent div to also be at the bottom.
your css would be something like -
div#container{width:200px;height:200px;
border:1px solid #666;
position:relative;
}
div#bottom{
width:100px;height:100px;
border:1px solid #f00;
position:absolute;bottom:0;
}
here is a sample jsfiddle - http://jsfiddle.net/LRy6h/
and one where the parent div is also at the bottom - http://jsfiddle.net/LRy6h/1/
and one with resizeable (dynamic) heights - http://jsfiddle.net/LRy6h/2/
and another one to match your updated image - http://jsfiddle.net/LRy6h/3/