I've been out of the Milw. area for nearly 25 yrs. now so I can't help you in the specific shop department BUT any decent repair shop/dealer around would be sufficient. Just make sure you stress the right oil for the car or they'll probably assume that you're using 5W-30 & go with it.
There's a local guy up here that I go to & he's more than happy to do the actual change, I've even supplied my own filter & oil. Like he's told me in the past: it doesn't make any difference to him, he still makes money off of the labor. I can certainly get the oil a lot cheaper by the case!
Living downtown probably doesn't give you much access to your own garage, I'm assuming.
You do, of course, know that you're probably driving city planners insane: you live downtown & drive to the 'burbs. Isn't it supposed to be the other way around?
BTW, what ever happened to the smooth, wonderful Milw. streets? Last time I was down there visiting my sister Silver Spring Dr. was/is a disaster! I don't think I've driven ANY roads up here in sticksville that have been that bad!