[Theme: Sample} How to center image in header?

Dear WP community,

I’m trying to center the header of my website (http://www.citymonk.com), without much luck. Does anyone know how to center the image?

Here is my code:

.site-header {
	background-color: #fff;
}

.site-header .wrap {
	padding: 40px 0;
	padding: 4rem 0;
}

/* Title Area
--------------------------------------------- */

.title-area {
	float: left;
	font-family: Lato, sans-serif;
	font-weight: 700;
	padding: 16px 0;
	padding: 1.6rem 0;
	width: 320px;
}

.header-image .title-area {
	padding: 0;
	height: 145px;
	width: 300px;
	background: url(http://www.citymonk.com/wp-content/uploads/2014/05/CityMon.png) no-repeat;
}

.site-title {
	font-size: 36px;
	font-size: 3.6rem;
	font-family: museo-sans;
	line-height: 1;
	margin: 0 0 8px;
	margin: 0 0 0.8rem;
}

.site-title a,
.site-title a:hover {
	color: #333;
}

.site-description {
	color: #999;
	font-size: 18px;
	font-size: 1.8rem;
	font-weight: 300;
	line-height: 1;
	margin-bottom: 0;
}

/* Full width header, no widgets */

.header-full-width .title-area,
.header-full-width .site-title {
	width: 100%;
}

.header-image .site-description,
.header-image .site-title a {
	display: block;
	text-indent: -9999px;
}

/* Logo, hide text */

.header-image .site-header .wrap {
	background: url(images/logo.png) no-repeat left;
	padding: 0;
}

.header-image .site-title a {
	float: left;
	min-height: 164px;
	width: 100%;
}

Would be awesome if anyone could help 🙂
Cheers,
Tijs