You can find this driver posted on the manufacturers website under the section "Network (22)"
. They shipped this notebook with up to 22 different network adapters.
Note: You will need to know what hardware is inside your pc before you can select the correct driver but I suspect it contains the one Dell calls "Broadcom 570x Gigabit Integrated Controller", however that's only a guess. You didn't say which type of network adapter you have, ie: WLAN or LAN. Dell used both in this notebook.