If she sits, you've got about three weeks until they hatch. If she doesn't sit and you don't want to incubate them, you can continue to collect them like normal and nothing changes. After three or four weeks her eggs won't be fertile anymore.
Without seeing what your cage looks like it's hard to say exactly what needs done, but basically if you get chicks you need to make sure the wire spaces are small enough to keep them in. They are tiny enough to wander right through regular chicken wire. I put cardboard around the bottom 4" to keep them in. Make sure they have a source of water they can reach on the floor but they can't fall and drown in. A chick waterer from the feed store, or a shallow bowl with rocks in the water so they can't fall into it, etc. Also chicks shouldn't be given layer feed because it has too much calcium and they can't handle it.