Oh, if it were so easy! Unfortunately, property taxes do not usually come down much as a result of decreasing property values. Depending upon your local rules, you can appeal the tax amount and/or assessed value of this home. In my area, Cleveland, OH, we can appeal every year between January and March, but cannot expect to see any decrease in excess of 10%, if that.
The underlying problem is that community services and school support rely upon property tax collections and these costs do not go down simply because house values have decreased. It's certainly worth appealing, however, $1 reduction is $1 in your pocket!
Best of luck to you!