I currently have a Radeon 6450 graphics which is not good for gaming. I want to upgrade it but my computer only has 300w and i dont know whether i could upgrade my video card without change my power supply too. What is a normal video that could play games like League of Legends at mid settings with no lag. I dont want to change the power supply, i just want to get a better video card, but i dont know which one to get. It doesn't need to hella good, but good enough to watch 1080p movies and play games without lag. Please help and thank you