If there are any eggs left you will need to remove them from the filter. With care, it is possible to roll them till they come off then carefully transfer them to the trap. It might be easiest to position a net under the filter so that any that fall will be caught. You would just need to empty the net into the trap.
Keep an eye on the eggs and remove any that turn opaque white. A plastic pipette is ideal for this - I always saved them from packs of medication but I bought some longer 1 ml ones off Ebay that are better because they are longer.
Once the eggs hatch you will need to feed the fry. When first hatched they need very tiny food. Do a search for how to culture infusoria, you have time to start this. As a second food, microworms are ideal. Starter cultures can be bought from Ebay, you will also need at least two cheap plastic tubs with holes stabbed in the lids (so the worms can breathe) and some cheap instant porridge. Adding a bit of dried yeast also helps the worms grow faster.
If these eggs don't make it, the cories will probably spawn again. And they could well have laid more eggs where you can't see them. From about a week after the eggs were laid, keep a close eye on your water change water as cory fry are very tiny and you'll suck them up without noticing. If you use buckets to do a water change, pour the last couple of inches of water in the bucket into a container where you can examine it thoroughly before throwing it away. When my pygmy cories spawned, the fry looked like tiny little black bugs on the sand. When I used a magnifying glass to look at what I'd sucked up I discovered they were cory fry.