Yes, he has 4 gb of ram.
I would recommend a a small ssd and a good $100 dollar graphics card.
An Athlon II x4 620 is an okay cpu. Though, your integrated graphics are holding you back and will not allow you to play games.
Your power supply should be able to handle these.
Graphics - MSI AMD Radeon HF 6770 with free Dirt3 gamehttp://www.newegg.com/Product/Product.aspx?Item=N82E16814127599
SSD- This is an OCZ Vertex 2 40gbhttp://www.newegg.com/Product/Product.aspx?Item=N82E16820227610
Price before rebates $200
Price after rebates $180
These will TOTALLY speed up your computer.
If you want, add some ram, but these two things above will help you more.