Ya, probably easiest to just get a new hammer.
If you do want to bend the hammer, I find an oxy/acetyline set up, with a small torch, works best. A propane torch can get it hot enough to bend, but the flame is spread out and heats up a broad area, causing an overall bend instead of bending in a specific spot. If you use a small oxy/acetyline torch, say a 1 or 0 adjusted for a small pointy flame, you can direct the heat to exactly where you want the metal to bend, and not affect the shape of the surrounding metal. Very accurate and controlled. I try to put a little more heat on the side that stretches the most. You need to be careful not to melt the metal though. Bill