36 hours playing GTA San Andreas Multiplayer with my friend for new year 2014 at my place

My computer specs are

System:

Microsoft Windows XP professional Version 2002 Service Pack 2 (and the computer boots really fast)

Computer:

Intel(R) Pentium(R) 4 CPU 2.80 GHz 2.84 GHz, 512 MB of RAM

Graphics:

SAPPHIRE RADEON 9200SE ATLANTIS

Is there anything I should upgrade so that I can run new games. Now if I shouldnt then wich games would you recommend for this PC.