It's been two days? Are you coming back to give us an update?
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.
Ghilly