The only proper answer, is to ask the guy doing the welding.
Someone locally to you, able and prepared to undertake it, may demand more, or less, than another.
Is this part of the subframe? Or a bolted on part? If bolted on, take it off, clean it, and take it to potential welders. This is going to be thicker steel than car body, so the guy welding sills for MOTs might not be the best option. A local fabricator, or blacksmith, if you can find one, would be the best bet, but they won't do 'on the car'.
Looking on
ePER, I'd guess it is alloy, so that requires specialist welding. An amateur TIG around the outside is unlikely to penetrate, and it'll break again soon.
Finding a replacement, new or used, might be a safer bet, but there do appear to be different ones.
Important to determine why it has broken. The cause, if not addressed, will break all subsequent ones too.