"And that's supposed to impress me?" (3,4)
I believe the answer is:
big deal
(Other definitions for big deal that I've seen before include "In slang, I'm not impressed - by large wood?" , "Exclamation of scorn, belittling a claim" , "Handing out lots of cards" , "Successful piece of business (ironical)" , "Scornful response to boast (colloq.)" .)