Hi, I've got JewelCad, I'd be happy to make an STL from it.
Just doing the STL export is, as you noted in the description, really easy. Of note, CAD programs often make a lot of degenerate/highly-skewed triangles, sometimes with flipped normals, when they export to STL, and making an STL mesh that is perfectly watertight and will print nicely can be a bit trickier, hence my added $15. For that extra money, I'll advise you on 3D printing (including support generation)--just tell me your printer model.
Thanks,
Caleb