PLEASE PLEASE PLEASE be VERY cautious about putting any animal for adoption on craigslist (or any other free listing site). CL has become a HAVEN for people looking for docile dogs to be used as bait for training dogs for fighting, even when people ask for adoption fees or do interviews. I'm near Philly and this is a HUGE problem.
I'm in Philly, and volunteer with Animal Control and the SPCA. This is an urban legend. Both shelters have had great success with posting adoptable animals there and getting them out of the shelters. If CL is a haven for anything, it's spammers.
OP, a cash donation to a rescue may or may not help your case. If they don't have space or a foster home, then they don't have space. For calculating how much, the average cost of housing, sheltering, and keeping a shelter or rescue animal healthy is about $100 per day. If you cane offer to foster your dogs in your home until another foster home or a permanent home is found, they'd probably appreciate that, or at least do a courtesy post on their social networks for you.
Are you trying to adopt them out together? That will take much longer, pairs of dogs are very hard to adopt out.