Battery light came on New battery and the starter is only six months old

New battery and the starter is only six months old, battery light came on and went off a few days ago. Then she got her oil changed and since has been on a lot. I replaced the battery again yesterday, this morning it quit running and started up a few minutes later. This time the power steering is acting up, when it does act up and you try and start it the dash lights go out like it's a bad connection. I cleaned and sealed the terminals and still remains the same, after noticing some of the issues online with the Malibu. If changing the alternator unnecessarily isn't going to cure it where should I start.