Why are you talking about the GPU? It's all fine, and I do believe you can run GTA IV on high specs. Only reason why peple might think an i7 is a waste of money, is because of it's major performance as no game requires such a good CPU these days - But they will in the future. I truly believe you have nothing to worry about. If you haven't tried, then go to this site: http://www.systemrequirementslab.com/cyri/intro.aspx Roll down to GTA IV and do a test - This should clear everything you need.
Best of luck.
LOL "because of it's major performance as no game requires such a good CPU these days" No
i3 is a dual core i7
i7 uses more power then the i3
i7 generates more heat then the i3
Which means hes gets less gaming time and more heat
Possible, but who cares.
Im going to use this PC for school, editing videos + rendering and gaming BF3 and IV:MP on Argonath.
And it will work for those things fine!
Also, yes im going to buy a cooler fan, will this one here work/be effective on 4-5hours of gaming?
http://www.coolermaster.com/product.php?product_id=6610
Video Rendering and Gaming should be done a Desktop but hey what ever
For a laptop? 
You can get a 560M ...
Its not possible to change screencard on a laptop, is it?
Most likely no
Waste of money? it was the cheapest i could find in that "class"
Whats the problem with i7? Its better and stronger.
You could have saved yourself the money and got a desktop with an i5 2500k