Purebred puppies are hardly ever available in Rescue situations. In my 7 years of working with RRRI, I can think of only 2 purebred puppies that have come through my state (Arizona is 4th in the nation as far as # of rescue dogs, too, if I recall correctly.). If your dog is missing the company of another dog, why not offer to foster a dog until you get the younger dog you're looking for? Also, puppies are so easy to place that when they do come into Rescue, they often don't even make it onto the website -- they're vetted and placed, usually within a few weeks, if that. Often, these puppies are placed with homes that have already been pre-screened and are just kind of waiting for the right dog to come along, so if you don't have an application in with your local coordinator yet, I'd encourage you to do that if Rescue is something you're interested in.
I know exactly how you feel to want a puppy, but feel like the initial payment is a bit of a stretch. For all three of my dogs (all from RRCUS breeders), I had to plan ahead and save for those dogs, just like one would for any major purchase. They are expensive (and then with all the standard puppy expenses + a dogwalker to let the puppies out midday...it all adds up.). But...in my opinion, a quality puppy with a pedigree of health tested and conformation CH relatives that came with an extensive health guarantee and a breeder's support was WELL worth it and something I was willing to invest in vs. a lower purchase price.
Litter announcements / solicitations are by approval of the Administrator/CoAdministrator- only.