hi mel cur, I thought frontline was supposed to kill the ones around the cat/dog as well? maybe its just in the bedding IDK??
I have n't heard of the borax thing, the only thing I know of is a flea bomb, because the eggs can be in your carpet/bedding/floor board cracks etc, it's the only way I know of to get rid of them all.
its a huge task, but can you pack up all your childs stuff and take somewhere else and stay somewhere else for a weekend while you treat the house? hehe, easier said than done , I know! jus a suggestion. maybe a vet might have more ideas, or pest control??? sorry.