You are right, Kelly. She did not say "when are you going to." Great job picking up on this! :)
She actually said "when are you gonna." This is not proper English but a very, VERY common way of shortening the phrase "going to"... probably happened because the sounds of "g" and "t" are really awkward together, and is a difficult sound to make. In many cases, in spoken English, "gonna" (although not a real word) is more common than "going to."
Source: American English (self)