Lots of sound advice posted above.
Common stress point on loaders, I repaired one of my buddy's, 1986 Kubota 2850 with Woods Du-Al 105 loader. Many years of being used beyond design ratings (read: heavy abuse by many, including myself!) lead to the left arm breaking off like this one posted, I repaired as described, welded where broke, plated over welded seam, added gusset in corner from horizontal member to loader arm, and returned to service. The other side had been broken also, and repaired previously.
$500-$600 for a competent welder to come to you and make quality repairs is reasonable in my book. I would prefer the repairs take place with the loader still on the tractor, to ensure correct alignment and no twisted frame issues.
Good luck... let us know how it goes.