Nanny/babysitter pay rate advice, help?

I just moved down to live with my mom here in Austin, TX. Instead of me going out getting a regular job, such as back at Texas Roadhouse as a food server, I am stuck having to babysit her 6 year old twins (my half brother and half sister) everyday. 3-8 on weekdays, 8-8 on Saturday, and 11-7 on Sunday. I get paid $150 a week working 45 hours, which adds up to less than $3.50 an hour. She definitely has money and knows I am not okay with the price I am getting paid. Any suggestions please on how I could try to talk her into paying me at a higher rate? This is ridiculous. Nanny/babysitter pay rate advice, help?
You have free rent and utilities living with her I assume - so you're actually not getting such a bad deal.