Hello, I are there Graphics Card For a Dell Inspiron 530s Desktop? to upgrade?
With a slim line case you are limited to a low profile card. With the small PSU you are limited to a card that gets all its power from the PCIe slot (75W). Therefore, your best bet would be something like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16814161397