First, kudos to you and your vets for doing such a wonderful job with both Mama and babies. Yours is a story that could have easily been tragic but is instead very heartwarming.
I have seen several mentions of giving Tums to Mama for a calcium supplement. You would be much better off giving her an actual calcium supplement. The reason being that a proper supplement will have a balanced ratio of phosphorus and magnesium, along with the calcium, while Tums has only the calcium.
Phosphorus is needed to prevent a deficiency, which can occur while taking calcium. Magnesium is needed to aid in the absorption of the calcium. Without it, the calcium won't do much good. Tums is good for what it's made for, but it's not meant to be a calcium supplement. Here's a link with some info. Though it's about humans, it's generic info about the balance between calcium and phosphorus.
Calcium supplements should contain phosphorous too, says study
What I've been using is 21st Century "Pet Chews Calcium". One tablet is enough for a 20 pound dog. I break a tablet in half and give 1/2 tab twice daily (actually I break the halves in two and give two quarters at a time). It's chewable and most dogs will just eat it. PetSmart sells it but there are other comparable brands.
The pups will tax the Mama's calcium the most from about the third week until weaning as their milk intake will be the greatest then.
One other thing I like to give my new Moms is beef liver. It's very nutrient dense and really helps them to bounce back from the stresses they've been through. I just boil it up and give some daily, though they don't get it exclusively. I also save the broth and pour it over their food and they love it.
Best wishes for all.