I have gone through this twice & have 06 rescued cats & a Cocker-Spaniel inside now. My Vet's advice was to ensure a safe warm dry place that she can have her kittens-she will disappear for a few days when she has them then will return to you or even move the kittens to the place you provided & will need a lot of nourishment-food/water. She will NOT do well inside w/your other cats & it will stress her out more. The kittens NEED to be nursed by her for at least 07 weeks so after 02 months, find good homes for them, then you can get her spayed as when they are first born they need constant nursing & after 02-04 weeks, need nursing every 02 hours so she can NOT be taken away from those kittens until then or the kittens could die. I am enduring a very SAD situation w/02 mommy stray cats at present & know these facts via my Vet & the Humane Society here due to others neglect & lack of logic. My e-mail is newangels@peoplepc.com
Good Luck & yes she cries for food & your security!