Care for feral mother cat and single kitten

So this feral cat took shelter in my balcony with a single kitten. It used to come and go but now that I've fed her a couple of times, she stays in the balcony. She goes out at her convenience but usually comes back in the evenings. The kitten isn't more than two weeks old and has just started to stand on his own. The problem is, there's a tomcat around which tries to come into the balcony through the grill. Also got to know from a neighbour that the same tomcat had killed the other 3 kittens in the litter when they were out. It looks like he wants to kill this one too. 

I want to take in the mother cat and the kitten but not sure how to work this out. I had kept the box indoors in which the cat and the kitten stay, for a night in fear of the tomcat. But the mother seemed to be really upset and kept mewing and scratching the door which is why i had to leave them out. Although the mother is okay with me feeding and petting, she growls a bit if I try to pet the kitten. I'm scared to leave them out because the mother goes out leaving the kitten unattended and the tomcat keeps coming back. I had to shoo him away a couple of times

Any suggestions on how I should go about taming the cat and the kitten and take them indoors ? 

P.S : I've had zero experience with cats.

This is how they look.

Thank you for helping this sweet family!

She looks like a young mother, so she may be unaware of the danger.  The tomcat may be trying to kill the kitten to bring her into heat again.  Whatever the reasons, you are right to worry.

If you have am empty room or bathroom, that would be ideal.  Mom will be upset at first - any change will upset her.  But for the safety of the kitten, they need to be kept away from the tom.

Do you have access to a large dog crate?  You could use that, with a blanket in it and a small litter box for her.

Try to bring her in soon.  Feeding her good wet food will give her a good reason to stay.