She had bra fixed by top woman dealer for buttons (11)
I believe the answer is:
haberdasher
'dealer for buttons' is the definition.
(a haberdasher sells sewing items like buttons)
'she had bra fixed by top woman' is the wordplay.
'fixed' indicates an anagram.
'by' says to put letters next to each other.
'top woman' becomes 'er' (Elizabeth Regina, UK head of state).
'she'+'had'+'bra'='shehadbra'
'shehadbra' is an anagram of 'haberdash'.
'haberdash'+'er'='HABERDASHER'
(Other definitions for haberdasher that I've seen before include "Dealer in dressmaking/sewing articles" , "Dealer in sewing items etc" , "Shop frequented by dressmakers" , "Who supplies a seamstress" , "Clothier" .)