Frankly, I'd go the route the others suggested and get a new one... Once it's bent, it's bent and even if you can straighten enough to get the blade back in, it'll still not work quite right.. There'll be a time when you're horsin' down on it and the blae will slide out again, probably taking a chunk of flesh with it..
Keep the blade though. Cutting it in half, then taking one of the halves and cutting into quarters, then cutting a couple quaters in half again will yield a brand-new set of Zimmerit tools...