You installed Ubuntu and the only access to the interweb is via Wifi (no ethernet cat 5 connection in sight for miles). However, your system is not recognizing your Broadcom wireless card. Your are in trouble.
First, you need to determine which card you have:
Mine is a
BCM43142 14e4:4365 rev 01. And I am running Trusty 14.04 TLS so I need to use
Next, you need to utilize a different computer (or phone, or phablet) to download the appropriate package. Save the .deb file to a separate USB (or whatever) and copy to your local system.
You can now either set up a local aptget offline repository or even easier - just right-click on the file from within Ubuntu and select “Open with Ubuntu Software Center” to install.