Help me turn an oval diamond e-ring into a pendant...

My mom gave me her oval diamond e-ring. It's set in a plain yellow gold band.

I have NO IDEA how to set it in a pendant...

any ideas/pics are very welcome!!!

My mother's first e-ring was a .50ct marquis. For my parents' 20th anniversary, Dad bought Mom a beauuutiful new e-ring. She had the old one (the marquis) made into a pendant. It is bezel set, then placed on TOP of (layer effect) another chunk of white gold with pave diamond chips (to make the diamond appear larger). The diamond is hung BELOW the links of the necklace. The links are yellow gold, creating a really nice two-tone look.

My mom is a petite woman, but this is definitely not 'too much necklace' for her. It is unbelievably beautiful, and it was under $200 to make. I'm sorry for the blurry pic, I really had to blow up a family shot to zoom on the necklace.
If you'd like info on the jeweler, she's in NYC and I'd recommend her anyday!!!