Pretty hard to tell off a computer screen what is going on there. Why not just find one on Ebay or at a junker that is in good shape and change it out?
That being a casting the crack is as likely to continue increasing in size as not. When you fracture a casting it's only guess which way the crack has radiated unless you determine it by dye penetrant inspection. This is a nondestructive test method that will only require taking the assembly to someone with a dye kit and the knowledge to use it properly and letting them test it. After cleaning you'll have your results in 45 minutes or so. Do not disturb the surface of the crack by brushing or grinding on it prior to taking it in as you will make the person doing th testings life much more difficult. (hell actually) That means no tracing, grinding or scraping on the crack surface etc because you will push metal into the micro fractures obscuring them making it very difficult to determine what is going on there for the guy performing the testing.
A good welding shop specializing in tig welding or machine shop should have a penetrant kit. Something like this:
Obviously your going to loose some clamping force with that pillar cracked off . Do you need all that clamping force? Maybe not?
There is also a slight chance you could also have a leg with inferior metallurgy. Something got left out of the alloy mix or the process went badly. Not very common in todays manufacturing environment but something you really want to know about because if the casting process was poorly executed the other side will also fail eventually.
Penetrant inspection will answer all these questions rather quickly.
If the metal is good quality and the damage is just the result of over torquing it maybe possible to just weld it and remachine it.
A good way to find the type of welding shop you want to use for this is to stop by a local small airport that has a air frame shop and ask them for a recommendation. They will know who in the area has the skill set you need.