How can I get some time to myself??

I'm staying with a family abroad, as an au pair, although i'm not getting paid. Anyway, the girl I'm looking after is almost 5 and is very demanding and time consuming. As she has no siblings, she looks to me for attention every second of the day whilst her parents are at work - from about 8:30 till 6:30. However, I really need some time to myself and she just won't allow it - except from her 'nap' in the afternoon. How can I encourage her to enjoy her own company?? I know that it is difficult for her because she has a new 'friend' now and is an only child... however, I feel stressed without any time to even think! Also, it's really difficult because she speaks French and I speak English - and although I can also speak French fairly well, she speaks very quicky and it's sometimes hard to understand her. Any advice? Thanks, I really need it.