Agree with previous posters...most regular office jobs are being paid at that rate and with no real work experience, it doesn't sound unreasonable although 7 days holiday and one day sick is definitely quite low. As to pay rises, it's entirely up to the employer and the economy... Many people didn't get much pay rises for a few years but in the last couple, employers have tended to catch up a bit. In you case, 10% wouldn't be unthinkable...
Best way is to see whether you can get a better job... Your relatives are not exploiting you badly but they are certainly not overly generous either...