You can actually use a copy of her own talkbackbot to do just that. Just wire up your own trigger like so:

    def contains_twsrs_response_quote(chat_line):
        return bool(re.search(r'~ [\w ]+$', chat_line))

Edit: This presumes the responses you're trying to detect match the form "Quote goes here ~ Author of Quote" seen in her quotes.txt.