I don't see what you mean by casting?
The lift link (can screw/unscrew) should be replaced. The lift arm that is bent costs 150-250 or so. Mine had 1/2 the bend yours does and I used a sledge hammer and got it straight (off the tractor). A blacksmith with a forge could heat and straighten it bit by bit on the anvil. The bent piece where the Top links hook to the tractor is probably still useable as is. I'd remove the tire and rim and take it to a dealer- see what he thinks. It still holds air and that is good - just hammer to straighten? Is the tire filled. Don't use heat- tire can explode.
For a manual- expensive 150 or so. Google tractor name + service manual or search tractor sites. Operator's manual are cheaper. I never trust my brake lock and don't use it to hold the tractor. I have a FEL. I lower the bucket to hold the tractor.
Good luck. I am not an expert by any means- just opinions. Take photos to a dealer- parts department and ask what they think has to be replaced.