What can we do about our cats? (they are not getting along.)?

As many of you know, a few days ago we lost our little cat 'Tabitha May', & I was against buying another. .. This morning, my wife was out walking & found an abandoned, starving kitten of about 6 weeks old that had been left on the railway tracks. She brought her home to see if I would accept her,& the little kitten took to me straight away,& now must be with me everywhere! (Her choice,not mine.) I didn't want to get another cat, but when I saw her & heard how my wife found her, I just love this little kitten. .. But, Frills, the mother of Tabitha May, does Not accept her into the house! Frills has been part of our family for about 10 years,so we cannot treat her any differently now. This little kitten who I have named 'Tabitha Two's', really needs our love & care & food & water, so we cannot abandon her either! ... In personality & things she does, Tabitha Two's is so much like Tabitha May that you'd swear that one cat was within the body of the other!! It is haunting really,but in a nice way. ... But, the Question IS:: What do we DO to get these two cats Miss Frills & Tabitha Two's to like each other?? ... The little kitten will go over to Frills, but Frills wil not let her close. She snarls,hisses,& the hair on her back stands up. Usually Frills is very quiet & says nothing. .... "What Can We Do to get Peace between these two??"