Download the latest driver from Realtek DIRECTLY

Here is the direct URL:

http://218.210.127.131/downloads/downloadsView.aspx?Langid=1&PNid=21&PFid=48&Level=5&Conn=4&DownTypeID=3&GetDown=false&Downloads=true

In case if the URL above isn't working, please go to www.realtek.com.tw first.  Then, on the top menu please click on Download.

Once you're into the download menu, move your mouse cursor to the left side(orange section), and follow the sequence:

Communications Network ICs -->Wireless LAN ICs-->WLAN NIC-->IEEE 802.11b/g/n Single Chip-->Software (Once you see Software, please left-click on this)

Then you should see whole bunch or chipsets. 

For our H50191, please check RTL8191SU(should be the first one), then click the GO button.
For our H50193/194, please check RTL8188SU instead.

Linux and Mac drivers can also be found there.