Judging by the limited specs you've shown if you want to get in to PC gaming you'll need a new system entirely, Dual core 3GHz isn't enough and with a GT 210 you may as well not bother, that's a bargain bin card from 2008. Your power supply if bought with that system is almost definitely not beefy enough as well and you need a new motherboard for a modern processor, 4GB of ram as a bare minimum. Scrap the whole thing and save for a new one