How to Wrap Header Text?

I am using a header widget to display a leaderboard ad, and right now the ad and the site title fit adjacent to eachother. However, if I increase my text size or add text to make the site title fill an area larger than 360px wide, it pushes the header widget to the lower-right of the site title, creating a big blank spot above and to the left.

What I would like to do is make the area where the site title is a fixed size, and force the text to wrap to multiple lines. Either that, or use a 360x90px image where the site title is, but I don’t think that’s an option without customizing.

Does anyone know how to make site-title a fixed width and force text wrap? Thanks in advance.