Letters of recommendation? Who to ask?!

I want to volunteer at a hospital but they ask for letters of recommendation. I haven’t gotten close with any of my college teachers yet so should I ask my high school teachers or would that be too far back? I also want to get a job bur this is my first job. I have worked with the public in middle and high school - tutor, volunteered at public info booth at fair, helped homeless. The problem is that I did these things for 40 hours not longer. Will that help me in getting a job? Or should I find places to improve customer skills say working at the library longer so that I can get letters from them and then use that to volunteer at the hospital?