first, if you want to try to let her hatch, I recommend more than just one or two eggs...at minimum I would try four. Some may not make it all the way to hatch.
21 days is how long they usually need to hatch out. Once the babies hatch, her job is to go from heating pad to teacher and protector. So yes, her broody behavior should stop (and be replaced with motherly behavior if her instincts are good and intact) once the babies hatch. Because she is the lowest on the pecking order, something would need to be done to accomodate her for the safety of her and her brood. If it is possible, just section off the area she has chosen to nest with some hardware cloth or something else to keep the others out.
Just in case, mark the fertile eggs, and remove any others. You can also try moving her into a cage with nesting material and allowing her to brood in there, but she may not cooperate.
Once the babies hatch, because she is low on the order, I would keep her and her crew separate for a couple of weeks, but where the rest of the flock can see them. Just remember, she may not sit the full 21 days needed to hatch, and if she does make it till hatch, she may not be a good momma. Just be prepared to pull the babies and raise them yourself if necissary.
If you would rather just try to break her of being broody, try to keep any and all eggs out of there. Collect them several times a day, and remove her from the nest. It took three days of this treatment to break my last girl of her broody behavior.