Michael,
Having prior olympic fencing experience is not required of newcomers to SCA fencing. Also, the modern fencing schools and clubs will be considerably more expensive than the $5 your local group charges per week. If you are currently attending meetings you are likely already paying some portion if not all of that rental fee. I can't give advice regarding the fencing itself, but you might want to do some aerobic exercise to get into shape either before or during your training. Running and bicycling are good. Fencing involves a bit of leg work. Being able to run backwards is also a plus.

Thanks, Fulke - I've been to the Nutley practice. (I actually live in Nutley). I didn't see any rapier practice, but it's certainly worth a try to contact Sir Tanaka again - he was very helpful and accomodating with me before. Thanks for the reminder!