Not much information on your card on the forum recently, you may care to look at this thread - there's a lot of it - but it's getting on for a year out of date now so I'm not sure how much is relevant:
Otherwise it looks like you have couple of options:
Start a new thread with your cards type in the title to see if anyone else has experience with an ACX100.
Go the ndiswrapper route. If you want to do that - and be aware that although I've used ndiswrapper I've no experience with your particular card - post back here and I'll point you in the right direction.