that SSD looks good.
sadly your motherboard doesn't support SATA III and it would run at half speed. if you don't care you can buy it and use it until you can upgrade your motherboard. it will still run better than your current HDD
anyway it will be a nice upgrade for your pc, but overall you won't notice big performance gain until you upgrade your CPU. the loading times like on zone change will be a bit faster
if you wanna check better what's bottlenecking you, you can run an application already installed in windows 7 called "resource monitor". it will tell you how much your pc is using of each resource (ram, cpu, disk) and you can filter it by application.
another app is process explorer by microsoft downloadable at
http://technet.microsoft.com/it-it/s.../bb896653.aspx. it can tell you also the GPU usage.