Spishkeys got a good point, but the likely hood is that if you have the mother in a small bowl with a single artificial plant then most of the babies will have been eaten. Next time have lots of plants or buy a breeding trap, for the latter you will need to know when she is going to drop as these can be stressful - thats why i prefer plants, be prepared though, mature mollies can give birth to up to 100 babies!!! if half survive that will take up a lot of space!!!
Best of luck,
Jonny.