I would take off all four,milk her out twice a day and then feed the milk back to the kids. If you don't have 8 litres of goatsmilk (they should get about 2ltrs per day for quite a while) - either from your nanny or any other goats you have got, buy Lamlac and make it up slightly more diluted than it says on the tin. Then mix the two together until you have the total amount needed for your kids. They should ideally get 4 feeds a day, after two weeks you can introduce some hay, and a bit later some creep - either calf or lamb.
Obviously leave them on for the first 24 hours, making sure they get enough colostrum each. If you aren't sure they get (and you have some anyway) I would give an additional portion of artificial stuff. If mum is standing well just milk her out and bottle feed the colostrum to the kids, that way you know how much they get each. Kids are much easier to transfer from mum to the bottle, compared to lambs anyway...