Problem is that we can't make specific recommendations on the forum
There is a directory of jewelers available under the Resources section of the forum, but my favorite Seattle jeweler is not listed there (yet, I'm sending a recommendation to the forum admin to see what is required to get them listed).
Foxfire in woodinville has a bench jeweler on staff. Not sure about the price of having a clasp fixed. He did make a necklace for me, years back, and it was $$$. Clasp should be less though