you need to have the alternator checked, try jumping it and getting it to orielly they should be able to test in the parking lot since you have a known good battery they should just be able to run an alternator check while the engine is running. i used to work at a parts store and saw this all the time, battery goes bad and kills the alternator as it takes more and more current to charge the failing battery(rare, but happened alot more than you would think), or the alternator fails and kills the battery so you replace the battery and are left dead again not long after. Thats why its always a good idea to have the alternator tested when you have the battery changed, it doesnt hurt, doesnt take long and can save you from getting stranded or help you find and fix an issue before it becomes major. its also worth it to check your belt tension too, as you may simply have a worn and loose belt not allowing the alternator to function properly.