Her name is Cara Quici, and according to her website she's a Texas native and current NYC and LA resident who describes herself as a "hardcore pop diva." Which once again begs that question — what was Sonja thinking? Whatever you think of Cara's singing abilities, nothing about the phrase "hardcore pop diva" makes Cara sound like the right entertainment for a classy anniversary dinner.
Also of note: Real Housewives was not Cara's first foray into the world of reality TV. According to IMDB she was also featured on the short-lived dating show Mama's Boys where she (unsuccessfully) vied for the affections of hot eligible men.
The Real Housewives of New York airs Mondays at 9 p.m. ET/PT on Bravo.