intel pentium g2020 a gaming rig?

will this pc ok for gaming not hardcore but just ti play games like wrc4, dirt 3, prototype and gta iv or maybe gta v someday...i dont needed it all at high settings just enough at medium graphics quality but no lag.

intel pentium g2020
4gb ddr3 1333mhz
asrock h61m-vs R2.0
80gb hdd sata II
plan to get a pci-e vcard later suggest me a better vcard that can play games above and settings at medium-high at 20-50fps
not gtx cause i dont have that much money

Id go for a bigger hard drive, more ram to be honest, and if you can afford it something quad core, Id reccomend a Amd HD radeon 6950 2gb, can pick them up for around £100
Nothing below 35fps in my opinion is playable.