I had to repair some seriously taco'ed UCAs when I stuck my front driveshaft through the back of my T-case a few years back. The stock arms are thin and only 3 sided, I think they twist ALOT during flex. I wouldn't recomment just welding in a patch, it'll probably crack again when they try to twist. I would cut out the entire area between the bushings, clean things up & weld in some square 1.25 or 1.5" tubing, nothing less than .120 wall.
They'll be fine that way, but if you just bandaid them the bandaid may crack again and giveout when you really need it.
BTW, why are they bent in the first place?