Nevermind I found it.
Take a look around line 1956 in your css and remove that code that you added – min-width: 475px min-height: 175px;
and replace it with this –
.header-image .site-title a {
float: left;
height: 110px;
width: 310px;
}
That will adjust the width and height to match the size of your image. The hyperlink is actually invisible and sits on top of the header image/logo. Once you adjust the hyperlink size it will show up right in place so when you click the image it will work as normal.