Can i control the direction that a drop-down menu open up?

I think it's impossible and i have a big problem with a site i've just redesigned and the drop-down menu is huge and takes the whole above the fold/center of the page, therefore i can't put any adsense ads around it.

In the old design i've made a decent revenue from adsense and now with the new design i had to put the ads on the sides and below the fold and the revenue went down drastically.

If i could make the drop down open only down i could put ads above it or something..

Any idea ?