After some inspection by the professionals, it appears that our ductwork was not properly installed (I know, I know, the inspector should've caught that, but now it's too late).
Today, they are fixing up our ductwork and while we are at it, we decided to go ahead and blow new insulation into the attic. Here's hoping this will help us beat the heat! (and get some more money in our pockets each month....)
Oh the joys of owning a home!