Think robot - not page visitor. This is where you might have to cross the line between artistic design and practicality. There are tricks which you can use to place the text at the top without disturbing your artistic intent. For one, the text can be written in the same color as your background. But be careful with that.
Some search engines check background color against font color and the trick can backfire.
A way to beat it is use an external style sheet even if it's for this one purpose. Since robots don't read the style sheets, it won't have anything to compare it to. Sneaky, but it works. The last thing and all to often missed is the 'text alternate' attribute of the 'Image' element. This only applies to 4.X plus browsers, but it is another way to get information across.