When the babies are weaned, take Mom to the Government's Animal Resource department near the airport. They will spay her for free.

Advise any one who takes a kitten to do the same, get the cat spayed or neutered (when it is old enough) there for free - stop the endless cycle of cats, propogating more cats. One female cat can have 4 - 5 litters a year, if you average out 4 kittens/litter that's up to 20 cats - this calculation does not take into account the litters the kittens will start having during the same time period.

You love your cat, get her spayed. You care about the kittens, make sure they get neutered too.
Signature line > "You can't fix stupid"