I started my car up last week drove for a half hour parked it for a half hour then it wouldn't start. Jumped it from another car for less then a min it was fine until a week later(today) and it did the same thing. i noticed that the headlights and dashlights were dimming until i hit the gas what is wrong with my car? radio works lights and clock work but wont start without a quick jump then seems fine for a while.