The problem you mentioned is a common symptom of a problem with the proprietary driver "wl" that this card uses. Fortunately, there is a native driver which usually works better than the proprietary one in newer kernels.
Originally Posted by mithen2
Please check which kernel you are using -
If it is 3.8 or later, please try -
..then reboot. You should have a working wireless, hopefully better this time.
sudo apt-get purge bcmwl-kernel-source
You may try above even if you have an older kernel, but the native driver wasn't as good on them.
If this doesn't solve your problem please follow the "Wireless Script" link in my signature, download and run the script as per instructions there, and post back the report it generates.
While posting the outputs, please use 'Code' tags. It preserves the output's formatting and makes the post cleaner, compact and more readable. To see a quick 'HowTo' with screenshots, please follow the "Using Code Tags" link in my signature.