Hi there,
I too studied journalism and am currently working for a national newspaper in Ireland. The great thing about journalism is that it (supposedly) reflects all walks of life so people with different backgrounds are always welcomed into the profession (ie doctors, architects, etc)
While you have an undergraduate qualification, a word of advice would be to take a course in journalism to prepare yourself for working with a newspaper/magazine.
I would not be completely sold on doing an MA - it won't get you any further than if you, say, did a course in Ballyfermot or any other college offering a journalism qualification.
Journalism is a trade - you need to know how to do the job rather than write a lengthy thesis on how people should do the job!! There is no pay or promotional differential between an MA or a straightforward journalism course.
By way of work experience, badger news desks to let you sit in a newsroom for a day and see if you like the working atmosphere. To be honest, you really learn your trade in provincial newspapers as you are expected to do everything from courts to council meetings, from a child's first day at school to a murder investigation. In the bigger newspapers, you tend to be more pigeon-holed. So try a local newspaper before a national one - you will get more professional attention.
The best of luck to you in your career - should I be watching my back??!!!!!