SegaXtreme

I'VE FINISHED ALL THE GRAFFITI AND GOTTEN ALL THE LITTLE ALIEN HEAD THINGS AND I'M JUST LAZY AND NOT GONNA BOTHER TO DO THE OTHER STUFF BUT WHERE IS THE GARAGE?!!?! I've been looking for it for two days. The map does not help at all cause when i get to where the garage should be, there is a wall! why?!??!? can some one tel me where to go to get back to the garage starting from that little save/change charecter point?