Am i being taken advantage of? I am a university communications student.?

[Eva]

I work 1 day a week as a Facebook marketing strategist for a cosmetics company, i basically do all the marketing and design of the page and i built the page from 200 to 1200 fans. Recently i asked my boss for a second day she said she didn't have the budget though there is lots for me to do but the following wee, the packaging girl brought in her friend and she has newly started working here with her. I felt hurt but i have reflected and realise i am a nice employee being taken advantage of. Granted she does pay me for days i don't come into work when i am sick and i get free coffees/cosmetics/food but she pays me direct into my bank account ($150 for the whole day) so i am not taxed but i don't mind as i want her to contribute to my super/pension and i question am i considered an employee, what if i am injured on the job? I haven't been given a raise or promotion for generating sales, fan and page engagement, nothing, she praises me but talk is cheap if you know. The nature of my job means plenty of fans post on the page every week and i spend at least 5 hours a week answering posts and i am not compensated for it. How on earth do i approach my boss, she has quite a reputation in the cosmetics industry here in Australia and i don't know what to do.

Sorry about my grammar, i am quite emotionally upset at the moment. If anyone has been through this experience or someone older and wiser has anything to tell me could you?

I have been there for 6 months now, i grew the page organically with less than a week of advertising and i earned what i got. I feel guilty though as i want to work for a reputable company is Sydney City, am i asking for too much by wanting a job like that but wanting to be treated normally and nicely?
thanks for answering my question. I am a casual and i am going to stop answering posts i felt bad but i have to stay strong and not answer, i realise that. i just always have that fear that if i dont answer the fans might get upset. Luckily i have a job elsewhere for 2 days for a skincare company and they are lovely people who treat me right. Actually as apart of my job i upload a lot of magazine and media press, her brand is pretty popular with media icons and celebrities here in Australia.