Need help with gateway laptop, battery wont charge?

for some reason my Gateway Laptop Battery will not charge on my gateway laptop, this is my first laptop and ive only had it for a few months, Im taking computer coursing at my college well n the next few quarters, but im still not familiar with laptops, please help me. oh when i check the Laptop Battery status it says "plugged in but not charging". How about buying a new laptop batetry such as Apple Laptop Battery or Sony Laptop Battery?