Ignition switch won't turn

I have a '92 Buick LeSabre LTD. It has been running trouble free for years. The other day after parking it I drove away and felt a bit if hesitation as though it was going to stall while making a left turn. I gave it some gas and no problems except that the antilock brake and service engine soon light came on. I drove a few blocks and decided to pull over and turn the engine on and offf to try and clear the service lights. The car was dead. The ignition switch won't turn to run, just to accessories and the transmission won't come out of Park. I tried wiggling the steering wheel and turning the switch, but it feels locked up solid. When I pulled over intiailly my battery was dripping fluid on the ground. I checked it's voltage and it was 11.2 or so. I did jump the starter and the engine turns over. Also my brake pedal feels very firm. I thought maybe the battery was fried so I changed to the exact match battery from a Bonneville, but still no luck. I'm thinking that maybe the alternator overcharged the battery and fried something. Maybe the key cylinder is jammed or missaligned. I also checked my maxifuses and they are OK. I am truly stumped. Can anyone help.
John S.

We parked the 89 Lesabre to pick up mail, it idled and dies like it was running out of gas. Put gas in , fuel injector stuff and won't start. Help I am a stupid woman