I would save a free Macrium Reflect or Paragon 11 backup image of XP so you can easily reimage it if you don't like Win7's performance. Wait for 30 days to activate so you can test it then easily move it to another computer without problems.
The Atheros wireless driver is likely in installer along with most all others, however put the Win7 or Vista driver for that model adpater on stick or CD so you can get online quickly to update drivers given by installer via optional Windows Updates.
Here are tips for getting a purrfect clean install - use the ones which apply: re-install windows 7
Note that if you wipe the HD and are using an Upgrade version of Win7 (as you're entitled to do with XP), you'll need to leave the Product key box blank during install, then afterwards do the quick registry workaround given here to activate Upgrade version on cleaned HD: Clean Install with a Upgrade Windows 7 Version