Unfortunatley I'd probably do the same thing just to get that pup away from that way of living though. My heart is too big and I'd have to save her. I know I can't save them all but I'd do whatever I could to save as many as I could no matter what. Thats just the way I am and always will be. Those poor babies didn't ask to be born, they deserve a good life too.
I agree though, I'd keep your babies away from the new baby. I wouldn't risk it. What did the vet say????
Can we see pics ?