At one time of the day there were plenty of part-time jobs (Nebenbeschäftigung) available on the market for everyone, meaning that public sector workers such as medical secretaries could pick and choose the jobs which were most appealing. Unfortunately, today with the econoimic downturn there is a distinct lack of jobs, and more job losses to come.
If you are thinking of becoming a medical secretary, then there are somethings to remember, which may hold you in better stead of getting the job of your dreams:

If you are looking to retrain, then it imperative that you get the right qualifications, so that you stand out from other people who may be applying for the same jobs as you.
It is imperative that you look to obtain all of your OCR certificates, these used to be known as RSA and you will usually require between an RSA II with both parts to an RSA III to become a medical secretary. The grade you will need depends on the job you are applying for, but if you are looking to become a secretary to a consultant, then you will require an RSA III certificate to do this job.
An AMSPAR certificate in the medical secretary qualification is always helpful if this is the first medical secretarial job you have applied for. The AMSPAR certificate gives you the vital work experience you will require in doctors surgeries, dealing with prescriptions and patients etc.

It is important to remember that even though you may have trained on a college, it is not always that easy to walk into a job and understand what you are typing, especially when it comes to medical terminology, if you are looking to work in a job which offers you medical notes to work from, then this is helpful, but if you are looking to work in the x-ray department of a hospital, then you will require a good deal of medical terminology, this is due to the fact that there are usually no notes as the consultants just dictate from the x-rays they have in front of them.

If you are wanting a job in the hospital sector, then a good place to start looking for training is your local college.