Hasn't gotten much past turning it on? 😕😱 Just kidding. I was all over mine the second it came out of the box, but I'm way more of a geek than she is. (Hopefully) 🙂
While you're looking for a router that works with your AT&T 3G USB modem, if you guys ever want to be on the Internet at the same time, the Internet Sharing feature built into the Mac OS should let her Mac connect to yours over WiFi and share the AT&T 3G connection active on your Mac.
You can set it up by clicking on the Apple | System Preferences | Sharing.
If you click Internet Sharing once to highlight it in blue and then click the question mark icon in the bottom right corner, it should give you a little help on the matter.
Have fun with your new Macs! 🙂