looks not too bad, but you should rework the header image, the left corners are pixelated. Also the company logo top left has not the right size and is resized by the browser what doesn't look good at all.
Furthermore, the pictures of the cars are much to large and some of them are even distorted, because the height and the width do not fit into the scheme.
On the nieuws page you should change the page options so that at least the login name of the administrator isn't shown (for security reasons). Due to the lack of real news you could remove the date when the news where published.