I would defenitely spay her. I wouldn't get another litter 'cause if you can't get rid of the puppies after they have been separated from their mother then you would have to cope to feed more mouths than you already feed. Also what would happen if you get an unwanted pregnancy? i mean she gets pregnant with another male instead the one you want her to reproduce with. You would enjoy Dixie to the best. You wouldn't have to lock her up and clean blood stains all over the house. Also you would be free of dogs waiting at your front door trying to matewith her.
Many unwanted puppies have been left in shelters 'cause of unwanted pregnancies.