"Getting old sucks, but it sure beats the alternative!"

If you're really wanting another dog, start talking to some of the rescue organizations in your area. Some organizations will foster dogs with older people - frequently older dogs that are otherwise hard to place - and the idea is that the dog can always come back to them if something were to happen to you or you were no longer able to care for the dog. And it's not uncommon for the organization to pick up some or all of the cost since you're a foster and don't actually own the dog.

Might be worth checking into?