Sick child not sure what to do anymore, HELP?

My daughter is 17 months and has been very sick for 3 weeks now. It started with an ear infection and a week later I took her back to the doctor who said she had some swelling in her lungs and brochial tubes. She was very wheezy and having a hard time breathing. They put her on more antibiotics and nebulizer treatments. I took her to the ER a week ago who said she than had fluid in the lungs and viral bronchitis. They said it was viral and nothing I could do. Her O2 level was 90 when awake and dropped to 85 while she sleeps. The ER refused to admit her, the doctor said that there was immidate cause for concern. I disagreed with him! So they sent us on our way home and I have been doing her neb treatments and she has improved some. The last 2 nights she has screamed all night long and ran a high fever. So I took her back to her doctor this morning who said her ear infection isnt gone and her lungs still have fluid and her bronchial tubes are still swollen. He wants to put her on prenizone oral and one for the nebulizer and another round of antibiotics. The cost for them is over 500$ we do not have insurance and can not afford that. Does anyone have any suggestions as what I can do. I am at my wits end with this and just need to get her healthy again!