So, my computer has a very weak video card (it's a Vostro, created for business needs, and so the video card has a hard time handling some games). My current video card is Intel(R) G45/G43 Express Chipset. My desktop is a Vostro 220. I've been trying to study up on what video card would work for my needs; I need at least a NVIDIA GeForce 6800 (around $40 on ebay).
My two questions: first, I don't want to mess with getting another power source. How do I find out what watts my computer has, and what video cards would be compatible with that? From what I've read online, a Vostro 220 claims 300 watts, and the 6800 claims that it's 350 watts, but most people say that, as Dell underestimates the power and most video cards overestimate the power, mixing 300 with 350 should work. However, I couldn't find reports of anyone combining a Vostro 220 with a NVIDIA GeForce 6800. And I'm not sure how I can confirm that my computer's power is 300 watts.
And second, where is a good reliable place to buy?