Unless you get another tank there is little you can do.
The traps described above work but they turn the tank in to something less-than-attractive. It's a good short term strategy, but hopeless in the long term.
Sight unseen, the catfish is probably less of a threat than the fighter and the female molly.
You don't specify how big your tank is, but if you have the room go out and invest in a few clumps of fine-leaved plastic plants and put them all in one corner at the back of the tank. The plan is to provide the young fish with a LOT of hiding places; they will be able to move about in the dense cluster much quicker than the fighter or the mother fish and dive through gaps that the bigger fish can't get through.
In short, give the fry a fighting chance to survive close to the way they are designed to survive, by taking refuge from the greater world around them until they're equipped to venture out.
Remember to drop some very finely ground flake food in, even if you don't see any fry.
Give it a week or two and in all probability you'll spot some small mollies wandering out to explore.
If you don't, too bad - for a fish life is a b***h, and then get get eaten... |