Hi Angel Girl,
I'm wondering if your plant is being grown as a tree form or a shrub form.* These shrubs are often grafted onto a single trunk to look like a tree.* If yours is the tree form, and it's the trunk that has broken, there is only a slight chance that you can save it.* Is there any way you can post a picture of the break and the entire plant?
If yours is the shrub form I would suggest you prune the broken to the ground or just behind the break with a clean cut.
Willows are prone to many insect pests and diseases.* Once there is a break in the outer surface, that allows penetration of insects and disease.* Of course you can give it a try, but don't be discouraged if what you have done doesn't work.
Willows are very easy to propagate.* You can either put the cut branch in moist soil or root in water.* Here's how to propagate landscape plants.
Here's some info on these shrubs you might find interesting.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.