Welcome aboard!
Re: Ignition tumbler- common problem with these cars. Mine was replaced about 8 years ago; haven't had any problems since.
Re: A/C- start by checking the belt first, as it tends to be the most common reason for A/C 'squeal'. From there, make sure the belt tensioner is adjusted correctly and the pulley is rotating freely w/o excessive play.
Do a forum search for both of these items, as there are probably several threads discussing/pertaining to both!