I can think of 3 options that may help:
- This is the sort of thing for which a secretary or assistant is really best. They can assess which calls would be necessary to forward to her, while taking the secretary's/assistant's time to explain what's on the site for those that aren't. Growth comes at a price, and it sounds like your client is at that point.
- Your client gets a second phone line, which would be used as the number shown on her website's contact section (or wherever those who've parsed the site would see it). Those calls could be forwarded to her original number, and so long as she gets a service that tells her which of her lines is getting the call, she can know (to some degree) which calls are more worthwhile.
- She can set up an automated message that directs callers to visit the website for information before following through with the call. This may deter some business, however, so this option would require weighing the current time lost with the possible lost business.
I hope that helps you out!