The only home treatment I could think of is warm/hot compress to help loosen things up, but I would think it needs to be aspirated or lanced, and that's not something most can do at home.
I took a look online to see if this would be horrible advice, and one site advised not waiting on the antibiotics, as in 12 hours could make it go anaerobic and gangrenous, big trouble. Another site had a less dire viewpoint.
Personally I would get an emergency appointment if she were my pet, like tomorrow, and wouldn't wait out the weekend, unless you don't think it's a real infection.
http://www.petplace.com/dogs/mastitis-in...page1.aspx
The problem with an infected cyst is it can turn into a volcano and rip a hole to get out; it will find a way to erupt. So if you can get it aspirated you can get controlled drainage.
Yucky, I know!
Note: in no way do I claim any expertise in this stuff and my experience such as it is comes from human beings and cats, not dogs.
But in your place, I would do the compress continually (until you run out of energy), like tonight, and I would also get the antibiotics ASAP. Compresses are a wonderful tool for nudging boils and cysts to resolve.