all the suggestions above sound very good. When I was a student, my statistics book was Bortz & Döring, but it only exists in German. I would suggest you go on the books.google.com website and have a preview for all the suggested books. This might help you get an idea what book is currently best for you.
There is also "Elementary statistics: a step by step approach" from cts books (where you can get a preview on google). When it comes to epidemiology, check out "Basic biostatistics for geneticists and epidemiologists" by Elston and Johnson. You can also get a preview on google.