There are lots of intresting cable about .....I'm selling some on ebay several sorts look for XL 315 or XLl189. Maplins do some good ones or Richer sounds ...where are you ?

Maplins do suitable 12v power supplies but you need to check that the loaded psu is not putting out more than 13.2v.

Do you have just the one amp ?

make certain you get just normal speaker cable [2 core] don't go to exotic, a decent signal from a cd player will be stunning. If you can swap out the vol pot and get a decent conductive plastic type you will be rewarded with fab sound.

Rechargables work ...but I find a regulated 12v 1 or 2 amp mains psu the best.