I'm surprised you want to give her away.It would be important for you to make sure her new owner spays her if you give her away. You wouldn't want another situation like how you got this little one! It's also extremely likely that she'd get out and get pregnant regardless of the owner's intentions.
Do you know what came of her mom and littermate?
Anyway, I applaud you, as always, for your care. You are clearly very thoughtful and your cats are very lucky.
Edit - I do agree that you need the support of a good vet, too. There are always emergencies.