For your sake and your dog's sake, don't make any decisions about spaying or breeding while you are frustrated or sad about dealing with this. Give raw food a try. I have been feeding raw for nearly 20 years and I am very happy with the results. It's not a cure all but it does make a positive difference. If your dog has yeasty ears, it is very likely diet related. Cut the carbs - no grains at all. Also, instead of salmon oil, try sardine oil. I use Nature's Logic. Check out the healthy skin kit at nzymes.com - I have seen it work wonders. Raw food doesn't cover up problems - it provides superior nutrition that helps prevent or correct them.
I attended a seminar by Dr. Jean Dodds. Though I have never used her allergy test, I believe she is very knowledgeable. You might also run a thyroid test on your girl as that could be a contributing factor.
It is very clear that you love your girl very much! I wish you the best of luck!
Absolutely try a raw diet if so inclined - if it helps your bitch, then great. BUT - if she doesn't have mites or something easily curable, DON'T BREED HER! Just because a raw diet might help her allergies doesn't mean you need to pass that issue on to the next generation. I think you've come to the same conclusion based on your previous comments. Good luck with your girl - I'm struggling with an allergy girl too - spayed her for that reason - never fun and always a problem here and there!