One Of My Female Finches Is Male?

About a year ago, my LPS sold me two zebra finches. As you can tell by the title, they sold me two zebra finches claiming they were females. I believed them, because I have had a male Finch before. These two "girls" looked like girls. I just didn't want a breeding pair.

Well, now I've got one! I knew that they had some eggs in their little house because they were getting aggressive. My female Canary did that. I cleaned out my aviary yesterday evening and decided to grab the eggs. And low and behold, I grabbed a baby. After freaking out, frankly I am still a bit shaken, I decided to do some research. The baby is about 8 days old, I believe: I can see his eyes behind the film, blinking. Not many feathers. He is about 1/2 the size of the adults.

I would take a picture, but their nest is deep and I have fake plants all over the aviary so they can have places to hide. The nest is conveniently behind one of the fake leaves.

I think there were about 7 eggs. When I rooted around (and found the baby), I saw that two of the eggs were broken so I removed them. So about 5 eggs left. And one big baby. I have read that after 20 days if the others haven't hatched I can remove them.

Here are my questions: Will the Mom keep laying eggs to replace the two cracked ones? Will she keep laying eggs after her baby is grown? I want to remove and put in dummy eggs (I did this for my Canary), but I don't want to unintentionally "abort" any of the babies. Suggestions??