Unwanted dogs are everywhere and sadly to many wind up in the local kill shelters. You can spare your dog by putting up some effort and finding her a good home. The first place to check is your local paper. Most papers charge nothing or minimal fee's to post a free dog.
You also will want to place small advertisers for the dog at your local pet stores, vet offices and dog pounds. You can also place your dog on free classified sections such as www.craigslist.com list the dogs attributes and let it be known the dog is free. A picture helps set your dog apart from other dogs. You can also call your local non kill shelters. Little Victory's is one, but you may have additional ones in your area.
If she is aggressive it will be very difficult to find a home, while I do not normally recommend the pound the reality is this is likely you last option. You can turn her over for a small fee.