Have you checked the see if the alternator is charging. If you put in a new battery and it runs for a few days and the same thing happens again it sounds like the alternator is not charging. You should learn to find out what is wrong before you just start throwing parts at it. You could probably had it repaired for less money if you had taken it to a shop and had them do it or had them at least find out what is wrong with it before they spent at least a couple hundred dollars.