How to start my car without the keys?

Ok so I have a 92 Plymouth Acclaim, this thing is a beater...but due to hard times I can not afford to buy a different car. Today when I was getting ready to start my car I turned the key and the whole ignition tumbler came out (I think that's what it is...it came out with the key in it) We couldn't get it to stay in or work. Finally a friend put a screw driver in the cyclinder (yet again I think that's what it's called...where the tumbler goes?) and turned it and was able to start my car. Well then part of the cylinder broke. Now it's just a completely round hole...nothing to turn to start it. I remember my Grandpa having a button under the dash on his 67 impala that started the car if the key wouldn't. Unfortunately my Grandpa passed away 6 years ago so I can't ask him how he wired this. Anyone know how to do this or another way to start and shut off my car? I have the keys so I'll just keep my doors locked when I'm not in it and use them only to get into my car. We live in the middle of no where so really not to concerned about security. Any help would be great!