Hi there. Sorry I'm not a company but I do currently work as a 'PA' (posh word for a Secretary really!). Just a bit of advice for you really. I started off my career (many years ago) as a Receptionist and basically worked my way up. However I did come to a point where I wanted to bridge the gap between 'Administration' and 'Secretary'. The only way to do this was to go to secretarial college. I did a 6 week intensive course in which I learnt how to 'touch type' (essential for any Secretary/PA), Word, Excel and Powerpoint - the 3 main packages that will be asked of you when applying for most Secretarial roles (especially in London for example, sorry not sure where you are based).
Also a knowledge of Outlook is generally always required as most Secretary's/PA's are required to organise diaries and meetings.
The only way to fully develop yourself is to go to Secretarial college, learn to touch type, learn the packages, get the confidence. Mostly at interviews it will not just come down to experience but to personality, enthusiasm and confidence that you can do the job, so if you have the skills this will come across to the interviewer.
You may not start off as an 'Executive PA' (for example), you may have to start off as a 'Junior Secretary' (for example) and work your way up and get the experience under your belt, but once you're on the ladder there are lots of opportunities within this industry and the eventual potential to earn a very good salary.
Good luck with your career, and don't forget secretary's can work in any industry, anywhere in the world, so it can be very rewarding!