Jo-Anne - Hockey Mom posted awhile ago about staying at the Airport Holiday Inn in Buffalo and being able to park the car there for free for two weeks. Would that be an option for you?
You can go to the website www.nfta.com it lists parking information and hotels. The rate to park is $32.00 per week or $7.50 per day. I ended up booking a room at the Radisson for cheaper than the Holiday Inn was offering. We are going for 2 weeks so thought we'd stay over, paking at the hotel is free but you have to tell them as there are different rates for Park n Fly.
Sun Park is right across from the airport and has a shuttle to and from. They drop you off at curbside for checkin at your airline and help with your bags. If, for any reson when you get back you had a flat tire or anything, they will change it for you. It is also patrolled etc so you car will be safe. I think its about 40$ a week to park there.