My cat just died she has 1 week old baby kittens!??!?!?

its really sadd, theres no sign of the mommy cat had disease before, first she had her saliva dropping and went to the rooftop but then she fell down, when she fell down she cant stand up and had a convulsions, i thought shes cold because of the rain & stuff, then when i put her in a box i left her like 10 minutes she doesnt move at all, i dont know whats wrong, and she have 1 week baby kittens 4 of them i dont know what to feed them, should i give them water/milk perhaps??? thx