Welcome to Seven Forums. Without knowing the exact model number of your laptop we can't go to Dells site and find the
driver or any other information about your system.
Without this information it makes it virtually impossible for someone to help you.
Your going to have to go to Dells site enter your serial number or find your model number and see what driver is available for your card.
Then their are several different methods to try and install it.
So please as asked above provide the model number for further help. Thanks. Fabe