A couple of things - first, if your car is draining its battery in a couple of days, you have a massive leak to ground somewhere. These things are a pain to track down - takes a lot of patience and trial and error, unfortunately. I have a 2003 BMW X5 with a similar problem - need to find a day when I can clear about six uninterrupted hours so I can tear into it. Not gonna happen anytime soon, so I have to put it on the charger if we don't drive it every couple of days or so.
Second, yes, it does sound like you fried your charger somehow. So, it seems to me that the sequence of events needs to be something like the following:
1. Buy a new charger
2. Remove the battery cables, and charge the battery directly from your new charger to get it fully charged up.
3. Do some searching on the internet for the procedure to hunt down a leak to ground. I'm not sure if there's anything on this site; I can't remember if anyone has written anything up for these cars. But it's a fairly generic procedure, so you should be able to find something on the net.
Good luck!