Need some help please old computer

Alright well i have a pretty old pc and i dont have enough money at the moment but i was wondering if i could perhaps buy some upgrades to make it somewhat decent i have a 150$ budget and i would like to play some of the more recent PC games. My specs are:

Windows XP Home - 200 GB Hard Drive

300 Watts

intel pentium 4 2.8ghz

ATI Radeon X300 SE

1 gb ddr sdram

Intel 915g proccesor

i was thinking maybe some RAM and a new video card but wouldnt i need a bigger power supply , thanks for readign and any help

Could someone please reccomend a video card and some ram please maybe a power supply?

You cannot buy any computer under $600 for gaming, unless you expect to play bare minimums. Work for a month or less and you should get at least $1000 from that, then you will have a good computer and not a 6 year old junk like I used to. You could get the 4670 like others have said, and 1 more gig of ram but your CPU is holding everything backRoman_UG