I will agree with Terry.
Your Video card is intergrated into your motherboard.
To change prossesor, you are only switched to a little above of the type prossesor family you have now, if you should have a stronger that can handle today's games pretty well make up in the Intel Core ™ 2 Duo or higher.
So first you need a new motherboard, that you can get support for new prossesor and video card with PCI-Exspress 16x input. Then you'll have new Ram pieces that fit the motherboard, new PSU that provides the power you need for stronger parts... Much to keep track of.
I would recommend to buy a new PC.