CSS fill remaining width

You can realize this layout using CSS table-cells.

Modify your HTML slightly as follows:

<div id="header">
    <div class="container">
        <div class="logoBar">
            <img src="http://placehold.it/50x40" />
        </div>
        <div id="searchBar">
            <input type="text" />
        </div>
        <div class="button orange" id="myAccount">My Account</div>
        <div class="button red" id="basket">Basket (2)</div>
    </div>
</div>

Just remove the wrapper element around the two .button elements.

Apply the following CSS:

#header {
    background-color: #323C3E;
    width:100%;
}
.container {
    display: table;
    width: 100%;
}
.logoBar, #searchBar, .button {
    display: table-cell;
    vertical-align: middle;
    width: auto;
}
.logoBar img {
    display: block;
}
#searchBar {
    background-color: #FFF2BC;
    width: 90%;
    padding: 0 50px 0 10px;
}

#searchBar input {
    width: 100%;
}

.button {
    white-space: nowrap;
    padding:22px;
}

Apply display: table to .container and give it 100% width.

For .logoBar, #searchBar, .button, apply display: table-cell.

For the #searchBar, set the width to 90%, which force all the other elements to compute a shrink-to-fit width and the search bar will expand to fill in the rest of the space.

Use text-align and vertical-align in the table cells as needed.

See demo at: http://jsfiddle.net/audetwebdesign/zWXQt/