Extremely slow connection with a Broadcom BCM4313 wireless card

Recently upgraded into 14.04 from 12.04 using ubuntu update manager. After the system restart, the browser is not showing the web pages(although the wireless network is present/connected and running). I would say the internet is extremely extremely extremely slow, because few bookmarked sites showed some bits of site contents 1/1000 times. And the the loading circle symbol turns to orange most of the time, anyhow displays nothing.

wireless driver(proprietary) : Broadcom BCM4313 wireless driver lenovo G580 laptop intel i5

• I am not in a situation to connect my lap using the network cable. So looking forward to alternate solutions

• Here is the link to the current wireless status/information of my system.

• Here is the link to the NetHogs results and the browser loading window(which shows the page title and loading symbol turns orange). My internet connection peeks 580KB/s in windows and 12.04

Any help is much appreciated

UPDATE : Connected to the network using USB tethering from my phone, and works like a charm. Which means wired connection is still on. Done some 20KB of update and still the wifi stays the same. It feels so great(relieved) posting here from my 14.04. The pain is still there, but i will live.

The final Update

A special thanks to @Wild Man for solving this nightmare of mine. And to you guys who took the effort to give a helping hand. YOU GUYS ARE THE BEST

Solution 1:

Please do:

sudo apt-get purge --remove bcmwl-kernel-source
sudo modprobe -rv wl
sudo modprobe -v brcmsmac

if there are any errors complete the rest of the commands anyway.

We may have to unblacklist some modules if the purge command does not do it for us.