You need to go through this forum,
http://forums.rennlist.com and
http://renntech.org and search for posts about all of the problems the bad ignition switch causes. Print a bunch of them and take them with you. If your warranty is getting close to the end, make sure it's fixed before it leaves the dealer. Be nice, but firm and take in copies of your research. Since yours is under warranty, they need to replace the entire mechanism with the updated switch and locking mechanism.
This kind of thing is why I never take her to the dealer. Many times they don't know what they are doing and they just replace a bunch of things that are just fine while playing the guessing game. By now they should be well aware of the ignition switch problem and that should be their first "guess".