One option would be to create a conditional comment that points to a different css file for ie6 / ie7 users and fix the issue in that file so it does not affect users with modern browsers.
You have ran into the IE6/7 broken float model.
Bring the floated spans before the text in your h2
<h2>[COLOR=Blue]<span>2007</span>[/COLOR]Dorint-Hotel in Binz</h2>
As a general rule of thumb floats should always come first in the source when they need to sit on the same line as other elements that are not floated.