Using Whitespace above main Navigation

Is there any way I can use the white space above the navigation bar to put say, my company telephone number?

 

To achieve this you can add a banner which contain your logo image at the left side and your contact image at the right side and upload it as a logo.
Use Photoshop to do that.

 

Thanks , I can create the banner in Photoshop but do I need to add anything in the css?

 

There is no need to add any css code, Just upload your banner as a logo image.