Google "lift the dot studs/fasteners" or the like. There are loads of retailers, for instance on ebay. I do not know how it it is fixed to the frame (I have the easy-up hood), but I suppose it is screwed, can't be much else. If the stud is broken completely flush with the frame it might be difficult to get it out, if there is a little remain it ought to have the shape of a nut so you can unscrew it with a little spanner.
