ignition?

[luvmypony13]

my car the other day didnt want to turn off. the ignition key cylinder just went round and round, so i had to kill it with the clutch. then the power stayed on and am not able to turn it off, so i disconnected it from the battery so it wont drain. i changed the ig. key cylinder and realized that it wasnt the problem, its in the housing, but autozone or any auto parts store doesnt carrie it. whats wrong? pls help. oh, its a 90 gt. thanks!!!