Doggie health question--- can anybody help?

[NMDemDist2]

my 10 year old border collie mix female has chronic ear infections. she is allergic to the lawn (but I'm not sure that's the issue with her ears)

we have done three runs of antibiotic treatments (both topical and orally together) the last one was several months ago. the ears just don't clear up and I can't afford another $500 dollar vet visit right now.

i clean her ears daily (sometimes twice) or at least every other day (depending on how she is doing) with an astringent acidic ear cleaner I get from the vet and it mostly keeps it to a dull roar and keeps the ear canal open and the swelling down to a minimum. but she still gets uncomfortable and the ear flaps get red and angry looking. I also give her Benedryl and aspirin when she is very uncomfortable.

i am getting a lot of light yellow matter out (I just pull it out with a q-tip as the solution works it up to the top, but never "dig" into her ear in fear of shoving the crap in deeper)

my question is how often can I give her the aspirin (or is there a better over the counter pain/swelling med?) and how often can I give her Benedryl? I am just trying to keep her comfortable until I can get her back to the vet (I fear we are looking at surgery now)

the symptoms are in both ears, but one is worse than the other

any help you can give me would be very appreciated, I so hate to see her stressed out, but I just can't afford a big bill right now.

Thanks so much!!