You signed a legal contract, and you must honor it.
Shelter groups work very hard to do right by their dogs, and you need to let them do that - they will find another home for her, probably very quickly. They may even have someone who wasn't quick enough, who actually wanted a puppy and didn't get one.
If you know someone else who is interested in adopting her, you can send them to the shelter so they can apply, but the first thing is to return her as soon as possible, so they can do what they work so hard to do best.
And thanks for asking, and being honest - because you are.
many years of raising and rescuing dogs