You would probably have better luck with San Andreas....But if your the type just to wander around shooting things at random GTA IV might work...one problem you will have is when driving the camera has a lag instead of following the turn right away...the only fix is to learn how to steer the car with the keyboard, and steer the camera with the mouse.
You are going to be pushed really hard with those specs.
Although the game 'may' run at the lowest specs but, after searching for your lappy on google, i noticed you may be running a GT240, which is not actually aimed at gaming as such so that is going to cause an issue or two.
If you do buy the game, i highly suggest looking for graphics twaeaks for the game.
As for the processor, yes, again you are going to be pushed but you should be 'ok'.
best bet is just hope and pray otherwise, either save and get a desktop or get a console, xbox or summin.
System Manufacturer/Model Number The HAFmeister (Custom) OS Windows 7 Ultimate x64 RTM + SP1 CPU Intel Core i7 950 3.06GHZ (OC'd to 3.99Ghz) Motherboard Asus Rampage III Extreme x58 SATA 6GB & USB 3.0 Memory 6GB OCZ Reaper HPC Edition PC3-16000 (set 1606Mhz 8-8-8-26) Graphics Card EVGA Nvidia Geforce GTX 570 Sound Card Creative SB X-Fi Titanium Fatal1ty Professional Series Monitor(s) Displays Samsung SM2433BW 24" Widescreen Monitor Screen Resolution 1920x1200
Keyboard Logitech G510 Mouse Logitech G9 Gaming Mouse PSU Thermaltake Toughpower 1200w (Modular) Case CoolerMaster HAF-932 Cooling Zalman Reserator XT and ZM-WB5 Plus - GPU uses Stock coolers Hard Drives Western Digital Caviar Black 500GB 32Mb Buffer SATA II
Western Digital Caviar Black 750GB 32Mb Buffer SATA II
Western Digital Caviar Blue 500GB 16Mb Buffer SATA II
Western Digital My Book Essential Edition 750GB USB
Samsung Spinpoint 2TB SATA II Internet Speed 3MB Profile - 350-400kbs (Real-Speed) Other Info IcyBox Hot-Swap Bay,
Logitech G27 Steering Wheel,
Xbox 360 Wirless Elite Controller with Microsoft Reciever and
Play & Charge Kit,
Belkin USB Wireless Adaptor,
GAME Generic Controller (Playstation Looky-Likey),
Epson SX125 All-in-One.