For this to work for me I had to modify the script as follows;
The only downside is if there are brackets in the book, it won't bring the page number in correctly.
on alfred_script(q)
set quote to first paragraph of q
set otd to AppleScript's text item delimiters
set AppleScript's text item delimiters to {"(",")"}
set bits to every text item of q
set pageNumber to item 2 of bits
set quote to first paragraph of q
return quoted form of quote & " (" & pageNumber & ")"
set AppleScript's text item delimiters to otd
end alfred_script