if you want to keep them, you need to get a filtered tank. dont get a HOB filter though, as the fry are easily sucked up into it. sponge filters work best with fry tanks.
you can go pick up a 10 gallon tank for less than 15 bucks and then a sponge filter and an air pump for like 20 or 25 dollars. to quickly cycle the tank, take some media from your existing tank and put it in there for a bit.
molly fry are big enough to take crushed flake food, but you mgiht want to start out with newly hatched brine shrimp.