Getting to Europe in the Summer

I need to get to Western Germany for one week this summer, and as you
probably know, flights to Europe are exorbitant in the summer compared to
off-peak times. Nonetheless, is there a website where you can put in a
general time frame and be alerted when the price changes? I have registered
with Travelocity, and they show you prices, but it is not with respect to
dates. I have scanned Orbitz and Expedia but really didn't see anything
there either. I guess, ideally, I would put in something like: Chicago to
Frankfurt or Dusseldorf or Paris or Brussels for a week in the months of
either July and August.

Any thoughts?

Maybe I ought to just got a travel agent.

Thanks in advance.

Mike
Milwaukee, WI