While I have never been Inside to see a temple wedding my friends who are married in the temple did a range of different things.
One of my friends had a real wedding dress. It covered her garments but temple dresses must be long sleeve, and up to your neck, and plain. Her dress was short sleeved and had beautiful beading and design on it. So for the temple wedding she and her mother made a plain white satin dress, that had a fuller skirt, for the temple wedding, she then used it as her temple dress when she went back. Once the sealing was done and it was time for pictures, she put on her wedding dress, and took pictures outside the temple, she then wore that dress for the reception/ring ceremony as well. Just for kicks, she wore a short white dress prior to going into the temple.
One of my friends had a less elaborate dress, and she just wore it for the sealing, ring ceremony, and receptions. It was short sleeve, when she went into the temple the workers loaned her some sort of underlay thing that added sleeves and enough neck coverage.
One of my friends wore her grandmother's wedding dress, which was long sleeve and had a high neck, it was made of silk with lace overlay, so it wasn't too elaborate. She wore this for her sealing, receptions, and ring ceremonies as well.
My parents were married in their house right after they finished building it. My mother was married in a green and white dress that her mother made. A year or so later they got married in the temple and my mom was married in an exact replica (again, made by her mother in white this time) with a few modifications to make it temple ready. She also took pictures outside of the temple in this dress.
If I was you, I would just buy a temple dress, and just get your wedding dress modified (if needs be) to cover garments. Add a sash or a little something to it, shorten it, lengthen it, add a train, ect., do whatever you want, and it will be just like a brand new totally different dress. It will be WAY cheaper than buying a brand new dress, and temple clothes. ($1000 for a dress you'll wear once, or a $50-200 to modify the first dress of your dreams, and maybe another $100 for a temple dress) You can take your pictures outside in your "new/updated" wedding dress, to look beautiful in the pictures. Then every time you go to the temple you can be reminded of the day you were sealed by wearing the same dress.
P.S. Sorry I wrote a novel I hope it helped
