FoxLondon

Hi everyone I am sure this is a pretty basic questions but I don't know very much about this type of thing. I've recently bought a new monitor so I can use two monitors for work. Now I realise I need a dedicated graphics card. I don't use my PC for games but I do need to be able use software that looks at brain scans (I don't know if a good graphics card would help with that). Generally I am just looking for the cheapest but effective model. My computer is a 530 inspiron (not slimline). Do I need to post any other details? I rang Dell and they told me I needed a GT 8400 card, which is around £55 but I just wanted to check if anyone had any other ideas or if this was appropriate. Thanks in advance. James