My daughter has been coughing and runny nose for about three weeks she has a fever of 103. She is on a steroid but still coughing what can I do?

See the doctor. An upper respiratory infection (head cold) can cause cough and congestion for a week or two, but if it has lasted for three weeks and is now associated with a fever, it is important for her to be seen.
Seek followup care. The best thing to do is take her to see her pediatrician, assuming she is a child. Runny nose and cough are not necessarily severe symptoms but (i don't know for what reasons) the fact that she had a fever of 103 and was given steroid, it sounds like she requires followup with her doctor for more medical evaluation and treatment. If it is not possible to see the doctor, she should go to er.
Go back. 3 weeks of unimproved symptoms probably warrants a visit to your childs doctor. Fever and cough that continue are worrisome. Some steroids can depress the immune system, which may make them more susceptible to infections. When symptoms don't respond rapidly to steroids, fever persists, and the child remains ill, a reassessment is probably needed.