Upgrading a Windows XP PC Tips?

Hey guys. You might remember me and this build somewhere. Yes I am the guy asking this on the game spot forums, but I'm spreading around to ask.



I currently have a Windows XP, and I want to upgrade to a Windows 7 64bit as well as parts of my current rig. I was wondering if it was possible?





Microsoft Windows XP

Professional

Version 2002

Service Pack 3



Intel(R) Core(TM)2 Quad CPU

Q8400 @ 2.66GHz

2.67GHz, 3.00GB of Ram



Processors

CPU Q8400 @ 2.66GHz

CPU Q8400 @ 2.66GHz

CPU Q8400 @ 2.66GHz

CPU Q8400 @ 2.66GHz (Or basically the CPU times 4)



CPU SPEED

2.7 GHz Performance Rated at: 5.94 GHz



VIDEO/GRAPHICS CARD

ATI Radeon Graphics Processor (0x9490) (ATI Radeon HD 4,600 Series)



FREE DISK SPACE

43.5GB



Basically what I want from this rig is to upgrade the OS to Windows 7 x64bit, RAM to 6-8 GB, one or maybe two of the Processors to an i5 2,500k, and a Video Card to a more recent one. I want to be able to play games greatly on it while doing work great as well. (Battlefield 3 is also a target game of mine).



What do you guys think?Upgrading a Windows XP PC Tips?
Intel Core 2 Quad Seems good enough for now, but if you can upgrade the video card and RAM, It would be a good gamer laptop