Any Window Contractor To Recommend?

[st002 1]

hi, i'd like to make good my existing windows in my 4 rm resale flat, but my contractor quoted me $700-$800plus for replacing the arms of casement windows at kitchen area and replacing all the rollers for sliding windows whole house, since his company is not bca approved for window works, he got to get from another company, i think it is very expensive, so want to c if anyone can recommend a better BCA approved window contractor. Thanks.