good news for the kitty and your sister, thank you for saving her.

Be sure you have the kitten combo tested for FeLV and FIV IMMEDIATELY at your vet, it is inexpensive. Please don't let kitty be around any other felines before the results come in NEG/NEG. Also, get a distemper vaccine series in her ASAP. These are the most important things to do for her, so a deadly disease doesn't take her from you and sister!

I'm sure you will figure out a perfect name for her!

Best of Luck!