I am sorry you are having a hard time finding a job as a medical assistant. I know in my state wich is PA, there are medical assistant training programs all over and they advertise everyday via radio, tv, internet and newspaper.
You have a certificate. You would have to do two years for your degree at a college or accredited institution. Many times Doctors are looking for someone with more schooling to deal with their patients. They do not trust 6 week "crash courses" to teach you all you need to know. You are basically the nurse of his/her office. He/She will not risk someone who does not know what they are doing with thier patients.
There are so many CNA's at my job that were sucked into medical assistant schools, graduated just to find no job. They work end up working as CNA's and they make the same as they would if they were mecial assistants. Higher pay comes with higher schooling and experience. I am not saying that Medical Assistant is not worthwhile because they are. The demand is different since everyone is getting into it. It is a lot harder to find a job but it is possible to land a good job as a medical assistant.
You should go for the CNA training and work as a CNA. You can use your CNA experience on your resume. You can emphasize the little things we do such as "decube prevention"(-changing diapers, vitals and ect. While you are working as a CNA, keep looking for a job as a medical assistant. Don't Give Up!
As I said before, I know too many CNA's who paid good money to accredited institutions, and still cannot find a job in the field that they went to school in. Check the demand of your dream. Do not just go for it because it sounds simple. These are the ones that will have you stuck in a rut!