Advise on ways to teach my lil sister Spanish?

I've been working at a health clinic for almost a year in Yuma, Arizona. I've learned a lot of Spanish. Mostly medical related, but still a lot more than all of my family (we are white from Ohio). I'm moving back to Ohio and decided that I want to teach my 7 year old sister as much spanish and I can while she's younger. Can you recommend any educational books(geared towards youngsters) that I can sort of make a lessen plan with? Or how I can implement it so she doesn't get bored?