You can add a height to the #header section of your css….or even the #header title area around line 685 –
.header-image #title,
.header-image #title a,
.header-image #title-area {
display: block;
float: left;
min-height: 120px;
overflow: hidden;
text-indent: -9999px;
width: 50%;
}
Notice its currently set at min-height: 120px