Alright you just need to go to ATI's website
Find your driver series download the drivers and install. And you will be all ready when you get your new card. But make sure you have your old drivers uninstalled before you install the new ones or you will end up with a lot of issues getting the catalyst drivers to install. I had this problem when i forgot to take the Nvidia drivers off my comp before installing my 5770 and its drivers.
Also its better to install the drivers this way then the ones that just come with the GPU because those are typically out of date and need to be updated out of the box anyway. This way you will have the most current drivers from the start.