No way to tell how long or how many. I had one that took 4 hours for only 10 fry, and another that took about 1 hour for 40 fry. Just watch the behavior and you should be able to tell when she's done - lack of shivery movements, back to eating normally, not hiding as much, etc.
The fry tend to hide, so if sitting still on the bottom is giving them the best cover then that's normal. Mine usually stay at the bottom for a bit, then go up and hide in the floating plants I keep just for them.
Feed them a variety of foods if possible, but feed often - like 4-6x/day 1st week, 4x/day 2nd week, slowly going down to 3x and then 2x over the first 6 weeks. Boil an egg and mix a small amount of the yolk with water and feed a small amount (don't mess up the water quality too badly!), crush flake food into powder and feed that (good for overnight), micro-worms, baby brine shrimp, or you can buy first bites food in the store.
Enjoy your fry!