Good grief everyone, stop and breathe!
Your kid doesn't have to do an art thing, a sports thing, a charity thing, and another thing and get all A's in advanced classes -- she needs to pursue her interest(s) in ways that are meaningful to her!
My older son is a senior, and has played soccer pretty seriously for years. He's academically advanced. He doesn't do art, he doesn't do another sport, he doesn't do a "charity thing" unless he's chasing girls (so there was some "visiting puppies at the humane society" a while ago). He still got into a couple of top schools. He wrote (and re-wrote, and re-wrote, and had edited by adults he respected, and then re-wrote again) some pretty darn hot essays, one of which described what he'd learned from playing soccer and being a leader on a diverse, top-20 high school team. My #1 piece of advice for high school juniors is to look up the essays on the universal application and start brainstorming, because the better that piece of writing is, the better you look on paper. And it takes some time to get a HS student to actually write something that reveals part of her personality.
However, your kid will be fine (better then fine!) even without going to MIT or Stanford. In fact, it'd be better to go to one of those places as a graduate student (preferably one who's getting paid). It's possible to encourage your kids' interests without making yourself completely crazy: again, this isn't about you displaying your status -- it's about your student finding a place where she fits in and can learn.
I agree for the OP one of you should see if you can step back to part time. I'd actually suggest that you switch off every year or two, so neither of you takes the entire hit to your future earnings. I also suggest setting up as many carpools as possible. They can be a PITA to organize, but a well-functioning carpool is a wonderful thing. And unless you have serious qualms about the coaches (and if you do, you should be addressing those directly) don't stick around and watch practices -- go for a run, or do the grocery shopping, or .. did I mention carpool?
Different kids are going to have different needs and desires for a variety of activities. I realize we're talking about a broad spread of ages in this thread, but the more you can empower them (to do stuff, to help around the house, to organize their own transportation, to cook dinner), the better it is for you and them both.
Also, in my town there are a number of folks (including me) doing professional work either as consultants or part-time. It's a local standard, though, and YMMV.