I'd go with 2 kittens, moggies or a breed that doesn't need a lot of pampering, so your other kitty doesn't feel left out.
I would keep the kittens in a 'safe room', some where that you can shut them off to the world but they get interaction, toys, litter, food and play time. Let your kitty smell them through the door and vice versa. Use a blanket and let the kittens get their scent over it and then give it to the other cat.
Personally I think feeding the cats on either side of the door works well but not straight off, give the kitties a good 4-5 days to adjust to their new home. Then when feeding time comes, put a door stop down, so the room door is open an inch and put down your cat's food first, then have someone put down the kitten's food. Do this for 2 days or until growlings finish.
Then bring all 3 kitties to a room, such as the kitchen, don't hold the kittens as your cat may see this as them being the dominants, let them get their sniffing and scentings out the way.
I would suggest that the new kitties be neutered/spayed, makes it alot easier on your current cat. A female kitten can go into heat from the age of 4 months, it will anger your now female cat, which will make the integrating process a pain and the house hold may get a few beatings.