Stupid question, but is has to be asked.

I live on a one-horse Island. A local company (whom I trust very much) has just been given a bunch of money to run fibre to the island through a deep sea power cable. My boss is pushing me to make the switch (leaving the final decision to me, which is rare and I appreciate a lot) but I am absolutely dreading having to update the wiring. The building is scattered with repeaters and CAT4 cables. The network/server room is on the other side of the building (400m or so). I want to make the switch but I am dreading having to run the cable and update the jacks. And just so you know, we get about 5 up and down right now, so there has never been a need to update the cable. We are on the fastest plan Bell Aliant offers and it is miserable. Please advise. My questions: • As someone who is relatively new with only general practical knowledge, are the updates necessary to the building able to be done by one person? •It it worth switching to fibre? We are a small business that only runs about 20 clients at any given time. Everything is a part of a CISCO system. Another option would be to wait about a year, update to CAT5e and update our Aliant package when they bring more speed in (50 up and down).