What can I do to make a gravel driveway driveable?

We got 2 dumps of gravel (pretty fine stuff, maybe 1/2 inch) on our downhill sloping driveway and now it's almost impossible to drive up the hill. The tires spin, the vehicle skids (and shoots gravel all over the place). Before that, the driveway was dirt and was driveable. We paid money, got gravel, and can't use it. Will gravel settle over time? Should I argue with the contractor (and make him remove some of it)? Note that black-topping the driveway is not really an option (lack of funds + the type of gravel we got is not for blacktopping). Any advice? Thanks...