An automotive locksmith is your best bet. Your 1998 Camry uses a transponder key, and if you still had a working key you could program it in yourself for a total of about $20. Without it you will need a locksmith to cut the key (dealers do not normally keep key codes for vehicles over 10 years old) and to program it into the car. This would be a good time to get a spare made for about $20 more.
www.remotesandkeys.com