Murderous Betta's ,,, pls someone help me!!!!!!?

i bought 2 female betta fish from shop an istant told me they wud b ok in a community tank (pls be aware i am only fishkeeping since december now they were grand all week, now they have gone Mental iv noticed dead fish in my tank every day with insides eaten out, and 2nite iv witnessed it firsthand the murder of a fish and now it is being eaten, im afraid to remove the fish being eaten by my Betta's in case they turn on another and kill again, i want to remove these fish now buy i have no other tank to put them in set up, i don't blame these fish as iv just read up on them an it seems to be their nature but i wud like to remove them now before they do more damage, and keep them separate at least till i get another tank tommorrow or is that even too soon does the new tank have to be a cycled tank..... i just don't know wot to do,,, my hubby says flush em , but that's not fair i like these fish and i am saving to buy another 200ltr tank to house aggressive fish and they cud go in there but i need a solution as to wot to do with em now pls help me thanx x x x ps fish that have died so far 2 guppies and a red neon tetra :(