Hollywood logic would suggest that Barraza would be playing the mother of Portman's Jane Foster, but I can't believe Thor would really take time to meet Foster's family when a war rages on Asgard. But who knows? Our exiled God of Thunder has to take refuge somewhere, and I could see this being some kind of peaceful parellel to his rather threatening Asgard family.
Of course, if Thor's human alter ego Dr. Donald Blake is in the film, then Barraza could figure into that as a fellow doctor or something like that. I certainly hope she has somethign cool to do. After seeing her fight the Lamia in Drag Me To Hell, I'm convinced she could leave Loki a little winded.