I agree with sonnywimps. Except that I would get a grain free dog food. Better yet, a good raw diet!
I deal with dogs with yeasty ears all the time. You need to get R7 ear wash and flush out her ears every day once a day for a week. Fill up her ear canals with it and massage the base (outside) of her ears to be sure you get a good cleaning. Depending on how much of that brown stuff is in her ears, you may have to do this a few times in a row the first time. Also do this outside as she will shake her head like crazy! You don't need to swab her ears dry as this stuff has alcohol in it and it will dry up the ear and help to kill off the yeast. But you should swab out the yeast crud that comes out. Keep her on a leash so she doesn't run away from you!
There is a really great ear powder that you can get to put in her ears everyday for a couple of weeks, then go to once a week. It's called Wonder Ear. This stuff is fantastic. For the first week, do the flushing, then when her ears are dry, put in the powder. Do this every day for a week. Then you can flush out her ears once a week and put the powder in when the ears are dry. For the second week used white vinegar to flush out her ears, wait for the ears to be dry then put in some powder. Do this every day for one week. Then as upkeep, do this once a week to once a month. Her ears will clean up really well if you stick to this schedule.
If your vet gave you any ear medication to put in her ears, what they don't tell you is that you have to flush that out everyday and put more back in. The medication will go rancid and will keep the yeast problem going.
Hope this helps! Good luck.