Replacement Parts for In-Ground Grill

I need a new grill, and I’m going to try to get this in-ground grill up and running. This is a natural gas line that’s run from the house. It’s been unused in the seven years that we’ve been in the house. Does anyone know which parts I can use to replace this broken down valve so I can connect to a new grill(not yet purchased)?

I would like for it to continue to have a shutoff, and also be secure to the base which is still very sturdy despite the surface rust. The current “valve”, i.e. second parts from the top has a nut holding it to the base.

Do you think the second part can be reused and just replace the top part? That would make my search for the needed parts easier but obviously need it to be safe.