Slow GTA IV

Hello, my name is cesc FABREGAS ...........my pc hve......1.6ghz processor..........9500gt nvidia card......1 gb ram.......80 gb hd...... i wanted to kno tht............whn i started playing gta iv for the frst time.......it worked very slow...like ..it strated working like whn jst old man push a chair at an age of 80.......it was the performance of gtaiv ..on my pc........can u tell me tht......how i would be able to play gta IV as a normal on these requirements....plz plz...tell me..i am hardly waiting for ur answer......??????

THANKS................................................................................................................................