Do get a mains charger: anything for a PSP will do. The mains charger is quicker and you can read while recharging.
We have a number of Rafael Sabatini books freely available in the MR upload section. Just click on "Ebooks" on the blue bar towards the top of the page. Do a book search on Sabatini. You'll want either LRF or ePub format.
There's lots more Sabatini freely available at Project Gutenberg:
http://www.gutenberg.org/browse/authors/s#a640
Choose the ePub format unless you want to learn how to do a conversion.
You can buy books from anywhere that offers ePub or LRF format. You can buy in other formats if it is legal for you to strip DRM in your area, and if you are prepared to learn how to do this.