Is this a good computer idea

[sizz1e]

I am currently running everything off of my sony vaio VPCF12Z1E it has 8gb of ram, 500gb hd, intel i7 1.96ghz and nvidia 330m. I can play any game as of right now but i was gonna purchase a external monitor and a nvidia video card whatever one is the best out right now and use this Village Instruments : ViDock the one i would purchase is the plus. What it does is allows you to use a external video card using your laptops express slot and connect a external monitor to the video card there for i would pretty much have a desktop. My setup is going to be a 32 inch led tv using HDMI from the video card as the external display and my logitech g15 keyboard and my steel series wow mouse. Let me know some opinions before i make the purchase cause if not im just going to build a custom desktop.