Two of the most effective topical antifungals are Tea Tree Oil and Grapefruit Seed Extract. Grapefruit Seed Extract (not Grape Extract) is odorless, so your toddler may not object so much to its use. I've used grapefruit seed extract on a ringworm patch on my tummy and it was gone within a couple of days, so I know it works. I found I was allergic to Tea Tree Oil, but others have found it very helpful. A good source for Grapefruit Seed Extract is Nutribiotics, which you can find at your local health store. Over-the-counter antifungals like Tinactin or Lotrimin AF should also work.
The most important thing, though, is to keep applying the antifungal until you are sure it is gone (which may be several weeks after the area appears clear). Fungi can burrow deep and hide out until the "coast is clear", as is evidenced by some posters on this board who had trouble with ringworm reoccuring after it appeared that it had cleared.