Thanks guys and ABR10OT that's what I believe I'm looking at. I'm actually going to look at replacing the whole system. Our football booster club is willing to pony up the money (around $10K) to bring someone in to redo it.
PG that's a great idea and if we are able to get the new system I will keep that in mind. Not applicable here because some guy volunteered to do it in our community about 9 years ago so no type of warranty and I'm sure it's expired now if there was one.
We only have about 18 heads for the whole field but I want to get around 30 to ensure we are able to cover the whole field. Right now we have some areas that don't get enough water.