There are things that you can do with the diet that can help seizures. I would pop over here: http://www.ourdogsonline.com/viewtopic.php?f=3&t=4201
and have a homeprepared diet formulated. There's an extremely good chance that will decrease the seizures, and, with some dogs, they have stopped.
This is a pretty "thick" site, but there may be clues here: