Sounds like you want what is best for all kitties involved, I went through this 2 months ago with introducing an adult cat to my 2 other cats, and now I am fostering a kitten. Its a very hard thing to do, but it is possible. Its going to take lots of consistency on your part also. 1) make sure kitten has her own room, this is going to be a safe place for kitten to go, the other cat will learn 'this is her room'. 2) start by feeding them wet food together one cat on each side of the door. this way they can smell eachother and make a positive association. The reason they growl and hiss is because the new kitten smells weird. 3) after about 3 or 4 days of doing this, open the door, but make them eat at a distance, so they can see eachother, 2-3 ft away. 3) Highly recommend petting them, one right after the other, so pet the kitten, then your adult cat. This helps transfer smells and eventually they don't know the difference. 4) Give kitten time to explore on her own time without the other cat around. Also, exchange some toys (so put kittens in cat's area, vise versa). 5) Get a spray bottle with water for discipline. 5) Make sure you have 2 litmassageplanetoxes, 1 litter box per cat is recommended. Give it about 2 months, they eventually will be able to tolerate eachother. They are more likely to run away and avoid a fight than be confrontational. I also recommend getting the female spayed, your other cat might start peeing around the house to mark his territory. Don't force this, they have to work it out themselves for what makes sense to them.
Make sure you are giving both kitties lots of attention and love, I am sure you will be fine. Good luck to you.