Spartan22, I am so sorry to hear that your broody hen did not accept the 2 chicks!!  I have another broody hen that hatched 2 chicks (finally!!), she kept killing several as they were hatching.  I haven't tried to slip her any other chicks, as I am afraid she would not accept them.  When I introduce a chick to a broody, I go out at dark with a flashlight.  I either cover the flashlight so that it only lets out a tiny bit of light or I turn it off once I get myself in place.  Then I slip the chick under the broody.  I usually try to put it right under her.  Sometimes I get pecked for my efforts. Then I turn the flashlight back on so it just barely lets me see what is going on.
If the broody is pecking at the chick, I take it back away, otherwise I leave it, but I go back out after a little while and check to see how things are going.  If the chick isn't under the Broody I will take the chick back. However, if the chick is still tucked under the Momma and she seems calm and peaceful ( I don't try to see under her, I just make my observations from a far) I leave the chick there.
I have only had to retrieve one or 2 chicks. 
You could try with another broody, however I would not recommend trying it with a first time broody.
I hope the rest of your chicks are doing fine!