Babysitting for parking spot! (haight ashbury)

I have a potential barter idea for families living in or near the Haight-Ashbury area: babysitting for a parking spot! I need a car for work and street parking in the Haight neighborhood has proven to be a real bear.
Parking spot rentals are very expensive, though, so I thought there might be a nice family in the area willing to trade a parking spot for 10-12 hours of free date-night/weekend babysitting per month.
I have 8 years of experience nannying in Evanston IL, Wisconsin, and most recently in Italy as an Au Pair.
I've nannied for kids ages 3 months - 12 years and am happy to provide references.
I truly love taking care of kids and miss it a lot now that I'm working my first post-grad job.
I know this is a a bit on an odd proposal, but I love a good barter and think it could be a real "win-win" situation for a nearby family :)