Can my Romanian Girlfriend come and live with me in the UK.?

Im English and serving in the RAF. we will not be using any social security and welfare system. I own my own home so we would not be using anything that was part of the social system. I would like her to work but as I understsnd it she would have to get a work permit. She is a qualified sport teacher in Romania but is that transferible to the UK? How long can she live here before she has to apply for residence? I dont want to be pressured into getting married because thats the only way.