Is there someone to help me have a garage sale before I move to assisted living?

Yes, there is a lot of action in that area. Look in your phone book or online for "elder movers," "senior movers," and others. Intereview some movers and see who provides the services you want. This is a growing niche in today's world, so there should be some companies in almost any medium size or larger community that specialize in helping seniors organize and get moved.
Good luck with your move,
Carol