You can do it yourself the way that springs used to be shaped in the old days. Having just done this myself, I can attest that it works. You need a large anvil and a big hammer. You work the leaf along its length against the anvil and hammer it into the arch you think you need. I recommend practicing first on a scrap leaf to get the feel of it, but its really quite easy. My dad worked in a spring shop for years and arched hundreds of leaves this way and he showed me how to do it. Or you can take it to a spring shop and have them rearch it on rollers.
B.