Charging sharper image Literati ereader

[zz2003]

Hi, I've also got a literati ereader on sale. It is working great for me and I love it. But I am confused about 2 questions,
1. How long do I recharge it? It says in manual not to overcharge but doesn't indicate how long I should charge it other than for the first time. Does anybody have the same thing and know how long it should be.
2. I got it from best buy. The salesperson told me it comes with a one-year warranty. But I couldn't find the information anywhere. Does anybody know how I can get the warranty, please?
Thank you so much.