Try dropping the resolution of the background bitmap.
In addition to what Larry recommends, try merging some of the layers if not all of them ( on a copy of the original "live" file ). Hard to go further without knowing where you plan on going with the file ( i.e., print size ). If you are planning for large format banner type output, then your raster effects and raster image resolution should be Medium Resolution ( or 150 ppi ). If you are going offset, then you're stuck with 300 ppi at 100%.