The only reason one should ever breed a dog is to improve the breed. Does the dog in question have attributes that you don't want to lose and feel like would be a huge benefit to the breed? Brulee is a beautiful dog and I'm so happy she found a home, but you really should never breed a dog "just to have one of their puppies". To me, that is a selfish reason to put a dog through a whelping. And what of the other pups? You can't keep them all. Whelping can be very dangerous to the bitch, especially if she's older or has already had several litters.
Is she registered with a legitimate kennel club (AKC, C[anadian]KC, UKC)? If you don't know, she shouldn't be bred.
Has she ever produced litters in the past? If the breeder didn't tell you and you don't know, I don't think you should breed her.
Does she have any titles? If she was indeed a show dog, she could have a championship. If you don't know, she shouldn't be bred.
Has she been health tested? There are MANY health tests that poodles should have before being bred. Hips, eyes, elbows, heart should all be tested, in addition to tests for genetic diseases. If she hasn't had any of these tests, she absolutely should not be bred unless you intend to get these tests.
I personally can't believe any reputable breeder would have sold you a dog that wasn't spayed, which means she probably didn't come from a great breeder (and you already said it looked like a puppy mill situation). This means that, despite her being gorgeous and having a great personality, she probably comes from bloodlines that have been bred over and over without health testing or regard to the dogs personality. This means that it's really a toss-up on what type of health and temperaments you would end up with. $400 is a pretty standard rehoming fee for an older standard, even if you get one from a rescue, so regardless of where she came from I think you paid a fair price and got an awesome dog out of the deal. I hope you and your daughter have many wonderful years ahead with her, and I hope you don't decide to breed her. I'm sure you can find a puppy from her "bloodline" without having to breed her, and even if you don't, there are many wonderful poodles in rescue, and tons of amazing breeders who are doing every thing right for you to choose a second companion from. Don't bring more puppies into the world for reasons that aren't sound and aren't going to benefit this breed we all love so much.
I don't mean any of this to sound harsh, just to be informative. If you really are interested in breeding, find a very good breeder to mentor and help you. Attend some shows, meet some people, learn more about the breed and what goes into breeding. There is a right way to go about breeding dogs, but there are so many people doing it wrong. Don't be one of those people, and don't get caught up with others who are breeding irresponsibly.