Here is driver version 1005.15.223.2011 for the ASUS BM6875 WLAN adapter. Note that the driver was released in October 2014 and was the last driver for this card. The operating system is Windows XP / XP 64 bit / 7 / 7 64 bit and if you have another system then you will need to search for this or run the driver in compatibility mode.
If you opt for compatibility mode then you need to download the driver and then right-click on the file and click on ‘compatibility mode’ which it will then install the driver in. Look for the setup file inside the zip file. You will have to extract the files first to do this.