I volunteer with MABCR, the group Rebecca suggested. If you wish, please apply! Read the website, it will give you a good understanding of how our process works. When filling out the application, please keep an open mind about the age of dog you'd consider and also whether or not you'd consider a mix. One gentleman adopted an eight year old female a couple of years ago. She adapted beautifully and is still his trail running partner!
As others have said, sometimes an older mix can be a dream. They're easy to house train, they're settled a little, and they're fully developed, so are ready to go with whatever your family has in mind (they can begin being conditioned to be your jogging partner, can start playing frisbee, or maybe agility for fun?). Puppies are tiny for so short a time...plus they chew, chew, chew, need frequent bathroom breaks, etc.
The screening process is thorough, and that allows us to determine which dog is best for you. We will not send you "more dog" than your family can manage. Plus there is support available for the lifetime of the dog if problems arise.
I believe that all of what I've said is probably true of most good rescue groups, so do some searching around, and follow your instincts.
Good luck! Michele