My husband and I took a wonderful biking/winery/tour of the Wachau Valley from Vienna several years ago and then our (adult) kids took the same tour 3 years ago with another couple on the RS GAS tour with us. At the time, it was called Grape Grazing and sponsored by Mike's Bikes. I just tried to google it (Grape Grazing tours Vienna) and got several links but so far not exactly the same as either of the two tours. I saw lots of reference to trip advisor reviews so you might want to look through some of those and see if any of them appeal to you and your wife. All that aside, I see you are specifically looking for something within the city, and while I was looking for the GG tours, I saw many referencing wine tours just in Vienna. Good luck; I bet you'll find something you will enjoy!