Don't have any suggestions that haven't been mentioned above (have been to the Big 3 in Lockhart & Salt Lick in Driftwood and can recommend all of them. Salt Lick is BYOB so take a cooler.
Speaking of beer, if you're into craft beer Austin has a lot of cool breweries. A good place to try some (or get some to go) is the Whip-In. (i'm at work & their website is blocked to me)
Another stop your wife might like is the flagship location of Whole Foods (at Sixth Street & Lamar) http://wholefoodsmarket.com/stores/lamar/