Gta4 run slowly

Hello,
I bought a new laptop [hp pavilion dv6-1215ee] for playing games its specs are


Intel® Centrino® 2 processor technology
• Intel® Core™2 Duo Processor P8700
• 2.53 Ghz , Level 2 cache 3 MB
Windows Vista® Home Premium with Service Pack 1 (32-bit
RAM-4gp
GRAPHICS CARD- ATI Mobility Radeon HD 4650 1gp dedicated ddr3
Hard disk drive speed
5400 rpm
I intall gta4 in it but it slow when i moved my mouse its little bit slow i am doing all low ,medium and high settings but it not better i am use game booster too but it cant help please help me and also tell me gta4 is better in vista 32 bit whereas in vista 64 bit please help
AND SORRY ABOUT MY ENGLISH