Assertiveness course Dublin?

Can anyone recommend a good assertiveness training course I'm Dublin? I have read quite a few books on this but realise I need a practical hands-on learning course. I am getting increasingly angry and fustrated at myself for allowing others to trample over me, for keeping my mouth shut when others make demands of me that leave me feeling undervalued, under appreciated and insignificant. I know it's MY behaviour that has to change, it's my voice only that can change this, because, you teach people how to treat you. I have taught people I don't matter, their needs are more important and valuable than mine, I'll agree to any demands made on me, I won't say no, their feelings are more important than mine; I need a practical course that will provide me with the actual skills to put this awareness into practice - thanks!!