Christine,
Congratulations on your daughter's upcoming wedding! Both of my stepdaughters got married after my ileo surgery, so I have some experience with this.
Like you, I started to shop for a dress in stores, but felt overwhelmed with the choices and trying things on, so I decided to search online instead and was very successful in finding beautiful dresses for both weddings. Here's a link to check out a variety of mother of the bride dresses offered at Dillards: http://www.dillards.com/shop/Women-Dresses-Special-Occasion-Mother-of-the-Bride-Dresses/_/N-ydnz?catalogId=301&langId=-1&splashlink=women_tile3_SpecialOccasion_112711&storeId=301
You can search online for a dress in a store that's in your town, so you can go there and try it on, or if you're feeling adventurous, you can order it online or go to eBay and search for the same dress, where you can usually find it for half the price!
Before you order online, make sure they have a good return policy and check out their sizing. Measure yourself to make sure you get the right size. Click order and voila, you just bought a dress! Once it arrives, try it on. If you don't like it, return it, and try again.
Since the wedding's in September, you have plenty of time to find a beautiful dress!
Happy shopping!
Cecilia