You can get the driver from here
http://sourceforge.net/projects/acx100/ Make sure you read the readme file. There is an excellent how to houseofcraig.net
If your card is the G650 the driver will not work yet, the 650+ works good, but rember this is still an alpha driver. The DWL-650 should work with the prizim driver unless it is one of the rare cards that actually uses the TI chip set.
I should also add which TI chipset, there is the acx100 and the acx111, the acx111 is usually in the DWL-G650 cards.
There you should be confused now