I'd heard that rumour howver I suspect they will wait until they see what happens with Renault. I hear Renault are still contemplating pulling out, but want to see what penalty Toyota get as they had signed the concorde agreement so are liable for a fine. If it's not too big, I think Renault will leave.
If I had the choice of Heidfield or Kubica, I'd take the latter, and I'd take my chances and wait to see if I could get him as well.