Where can I buy a video graphics card ?

The best place, best price, expertise and selection would be the Micro Center on Nutley Street. It is about 20 minutes from Alexandria. You could install it yourself, let the Micro Center install it or let ComputerHelpSOS install it. There is a big difference between Windows 10 and Windows 11, so make sure it will run on whatever operating system you have. Running on Windows is not good enough any more.