Do any of the hospitals near you have unit clerks/business associates, with your clerical experience you would be a good candidate to work on a unit dealing with clerical stuff-filing, dealing with admissions, organizing medical records, supplies, etc. You might be able to start as a unit clerk in a hospital and then later move into a nursing assistant. The hospital might even provide the nursing assistant certification classes.
Also, did you let them know in your cover letter/resume that you are planning to attend nursing school
. Hospitals are usually pretty receptive to nursing students because they look at students as future nurses for their hospital.
You might also want to apply in person, go into Human Resources, introduce yourself and fill out an app.
Good luck, hope this helps!