How can I inexpensively repair/replace the the DRIVERS SEAT?

What is your question?

My wife drives our 2006 Toyota Sienna. The DRIVERS SEAT has literally fallen off its mounting. She has found a use for those thick phone books delivered by TPC and has placed a brick & phone book under her seat to hold it in place. This is, at best a temp fix. What is the best low cost fix? Does the seat need to be replaced or can it all be repaired? Any other thoughts?