Not sure what to do with my only car and funds are not there for parts! Help!
 

I have a 1999 Diamante with the 3.5L v6 and I have a weird issue with my electrical system along with a oil leak. I have right at 200,000 miles on the car and it has been good to me and the only issue is a oil leak from front main but it has been there since 120,000 miles. Anyway I had a alternator go bad a couple months ago and I got a $150 replacement and it worked fine for a while. Then I started hearing a rattling sound from the belt area which sounded like a idler pulley going bad but it stopped before I go to fix it and shortly after noise stopped my lights started pulsating exterior and interior. I have been dealing with it because money is tight and I work 50hrs a week. Well my radio stopped working and I was given a new one as a gift but every now and then it turns off and back on and recently the car runs rough at idle now also. My question is could the pulley or old belt cause these problems or should I just go get another alternator? Now you can hear the motor pulsating at idle also that's why I am not sure what to do first and I am saving up money for whatever I need but if the car breaks down I am screwed due to work being 30 miles away pso I need to decide where to start soon. Any advice, ideas, or help would be great!