Why is my Broadcom wireless card not working even after installing the b43 driver?

I'm using Ubuntu 12.04. Network controller is BCM4311, lap top is a Dell Latitude D830. I've updated, upgraded, installed firmware-b43-installer, fwcutter, and it's still not detecting my wireless internet. iwconfig says no wireless extensions for lo or etho even though the controller is detected. Trying to manually add the wireless network through network manager also hasn't worked. It's just not detecting the wireless network.

Showing the driver is apparently working

And the output from lshw -c network:

*-network UNCLAIMED
   description: Network controller
   product: BCM4311 802.11b/g WLAN
   vendor: Broadcom Corporation
   physical id: 0
   bus info: pci@0000:0c:00.0
   version: 01
   width: 32 bits
   clock: 33MHz
   capabilities: pm msi pciexpress bus_master cap_list
   configuration: latency=0
   resources: memory:fe8fc000-fe8fffff

Output from rfkill list all:

0: dell-wifi: Wireless LAN
Soft blocked: no
Hard blocked: no
1: dell-bluetooth: Bluetooth
Soft blocked: no
Hard blocked: no
2: hci0: Bluetooth
Soft blocked: no
Hard blocked: no

What else can I try? All of the solutions I've seen have said that fwcutter and the firmware-b43-installer are the answer but they haven't been working for me.