Rough idle, irratic voltage, damn squeak

[tiki240]

ok, i havea turbo timer so then i first turn on the car (as of the last 2 or 3 weeks its gotten cold outside) i read about 11.45-12.37 and normal voltage is between 13.87-14.08. i alos notice that even though the car is idling properly at 700 rpms the idle is rough and seems to skip a beat. the biggest problem.... a loud squeal that sounds like a belt. it felt loose so i tightened it. and now, still the same. belt dressing helps for about 1 day and then fails to work. i have a date tomorrow night and would like to resolve this issue. its embarrassing to drive my car like this even with the SR. while driving, ill get about 13.8 volts and when i stop, i drop to 12.4 (bounching all around) and the squeal will last till it gets back to 13.87+ volts. HELP. thanks for speed u guys.