Hi Purdue,
I would do just as Summit suggested. If you do not find the owner, and you still want to do the right thing(spay the female), call rescue organizations in your area. Ask any local vet for numbers and names. Ask the organization(s) for help with spaying, shots, heartworm test and (hopefully) preventative, flea/tick control, and re-homing her.
It is a good thing for you to care enough to post this question. Now to focus on your male dog. It would be best to neuter him asap. Also, it sounds as if your dog either is let loose or tied outdoors. No matter what you may have been told neither of those are good choices. Too many bad things can and do happen. He will be safest and probably live longer if he is fenced or walked on a leash.
I understand he may be an outdoor dog. Please understand that dogs are, "pack" AKA "family" animals. Your dog needs regular interaction with you. My dogs are all indoor/outdoor dogs. I put them out in the fenced yard when they need to go out and to play. Otherwise they are indoors.
Best to you, your dog, and the female dog. I hope this helps. I hope you find her owner and that she is spayed immediately. Most of all I hope you have your dog neutered and can find a safer way for him to be with you other than having him loose or tied outdoors.