First of all, is she spayed? Whether or she is or isn't spayed, a visit to the vet is in order, but if she IS spayed, the chances that the hardening of the mammary glands is due to tumor growth are a lot less than if she isn't spayed. As far as her vulva being swollen, dogs can still come into heat at 12 years of age, so it's a possibility that she is in season. The hardened mammary glands has me worried, though, so I would call and make an appointment with your vet as soon as you can to get her checked out.
It's been two days? Are you coming back to give us an update?