Jimmy,
I would build a whole new rudder, myself. A kick up rudder like mine has a rudder head which is made up of two sheets of 1/4" plate Aluminum with Teak spacing blocks, and Stainless steel spacing bushings around it. It's held together by S.S. bolt that go through the bushings. The blade can be made of fiberglass or wood, or a combination of both. The blade pivots on a large bolt. My friend Keith made a rudder head out of sheet S.S. and used fiber bushings on his. He used a wooden rudder blade that he had from another boat. When the blade is down, it has to pretty much match the angle of the rudder blade you now have. If it doesn't go all the way down, you'll experience a lot of weather helm in your tiller. So the angle of the blade is critical. Here's some pics of Keith's rudder. Check "Owner Albums" on this site for my pictures under "Trinkka" and you'll find pics of my rudder, along with a lot of my OD 222 modifications.
It takes planning Jimmy, but it can be done. One of the guys in my club built a spade rudder for his O'Day 27. His rudder shaft has two flat plates welded to it. What he did was epoxy two pieces of foam over the shaft and plates. He shaped the foam to look like the rudder. Then he used a special stitched fiberglass cloth and epoxied it over the foam. Then he made a paste out of micro balloon filler and epoxy for the final coat. It came out pretty good. I would use epoxy resin, because polyester resins can soak up water, so I'm told. Check out any of Don Casey's books on fiberglassing. They're probably in your public library. Read up on it first, and then go for it.