Pull your alternator and bring it in to autozone. They can check to see if it is good or not. Might as well bring in your voltage regulator too, just in case
...it was running before but it sat with gas in the carb so I was told by one of my mechanics told me that i should clean it because it may have gotten gunk from the gas just sitting...
That's not logical. The car must have sat more than a week for your mechanic to come to that conclusion. When's the last time you actually drove this car?