You can get everything you need including the kitty (milk)
at Petsmart. Believe it's powered, so needs to be mixed.
Can you call a vet for help with this? I would wait to be sure
Momma kitty is not coming back before you get involved with
moving them. K & L ,or Moosmom on the cat bb will surely
know what to advise. Try not to let the Momma cat see you
watching her or the babies. Do not look her in the eyes when
placing food out. Put it out & then leave quietly.Hide & watch
for her & the babies.