Laptop improvement

I practically want my computer to be good enough for dolphin to be less laggy wii emulator.But also I want pcsx2 to work perfectly and wanna play some mordern pc games (namely assasin's creed).Some qustions:Does it take a good graphics card to make games less laggy?(i have the 4 chipset thingy)Is it possible some games will not run on my system due to the sound type?(as in Tears to Tiara)
Does changing sound card also change sound type?(if above q is yes)does it matter that I'm using the vista?does it make my games laggy?Does it matter if I have 64/32 bit?(i have 32 bit)My computer stats:
Surely I can do some improvements right?Heres what I have:
system model: Inspiron 1545
Bios:Phoenix rom bios plus version1.10 A07
Processor:Pentium(R) Dual Core CPU T4200 @2.00GHz (2 CPUs),~2.0GHz
Memory:3034MB ram
DirectX Version: Direct X 11Display Device name:Mobile Intel(R) 4 series express chipset family
Chip type:Mobile Intel(R) 4 series express chipset family
DAC type:Internal
Approx total memory:1293 mbDrivers
Main driver;igdumdx32.dd,igd10umd32.dllSound Device:Speakers/headphones
Type:WDMc'mon help me out over here pls Oh and also:Windows Vista sp2
using laptop

graphics card makes a huge difference, but its a laptop so you're stuffed. The only parts you can change are ram and hard disksound card is mostly irrelevant so long as there is onewindows vista is likely contributing to the problem

Hmm well as you can see my music type is wdm but tears to tiara(a game I really want to play) doesn't work on my computer for some reason.Apparently its sound type is PCM so I was wondering if that is an issue.and is my processor good enough to play games like skyrim,the last remnant and assasin's creedWell I was thinking of changing to windows 7 but would it replace everything I have on the C drive and should I get 32 bit or 64 bit?

2.0ghz is slow, it will struggle (especially considering the graphics chip is useless and just sends all the graphics code back to the CPU to deal with). Skyrim is unlikely to work acceptably if at all, the last remnant is quite old now so it may work.Windows 7 would be an improvement. It isn't required that you format the C: drive, you can do a straight upgrade, however, formatting and doing a clean install of windows 7 is very strongly recommended. Windows upgrades tend to cause problems further down the line.64 bit is the preferred option.