If you are using a blog to promote your web site, it's good to have a custom header at the top of your blog, not just the words. If you look up at the top of this page, you will see how I did it for myself. It's just an image taken from my web site and sized to fit into the space blogger needs.
Start with a simple blog layout. Go to the Design page. For the header, click "Edit", browse your computer for the graphic that you have created, and drop it in. Yes, it's that easy!
If you don't already have a properly-sized graphic, and you don't know how to make one yourself, hire a graphic Designer, like me. It shouldn't take more than an hour or so for them, especially if all they have to do is to visit your website, do a screen grab, and then modify it in Photoshop. Remember that Graphic Designers charge by the hour, so to get the best price, be specific about what you want, and please don't ask them to do the work first without making arrangements to pay them. You wouldn't hire a landscaper to come over and "trim a few plants" or "cut down a few trees" before you hire them, so please don't do this to a Graphic Designer.
My post on how to hire a Graphic Designer is here.
As of this posting, October 23, 2010, my hourly rate is $75 per hour. I would estimate that I can create a graphic for your blog by using your website for $112.50. I would email the image to you as an attachment, and all you would have to do would be to save it to your desktop, and then follow the steps above to insert it into your blog. And if you need to make changes, I will be glad to help. I'm always here in cyberspace!