Marketing is a very hard area to get into- even for marketing graduates. I'm a marketing manager with 5 years experience and even I would worry if I lost my job (real possibility) as there are much more candidates than jobs at all levels but paticularly at entry level. A lot of companies are cutting their marketing budgets in these times so marketing is being downsized in a lot of organisations. Sorry not to be the bearer of good news but times are very tough in the job market. It's so comeptitve and going to get even more so over the next year. However now is a good time to upskill and take a course in marketing. Even part time (you already have a business diploma which will stand to you but you should aim to specialise a bit more).
Another option if feasible is to look within your organisation. If you are in a larger organisation with a marketing department this could be an option i.e. speak with HR etc and ask them if a transfer is a possibility or if they could support you with your further education. If it's soemthing you really wnat to do, it will happen but perhaps not as quickly as you would like.
Good luck!