ok that is kinda weird that you put 4 quarts of oil through the top shifter, because there is a fill plug on the side of the tranny, and you say you only had 1/8 quart left in. well you probably have a leak, did you notice the oil leak from the time you filled it till now? it could be leaking from a few spots. And to get the drain plug out that is rounded you can do a few different things, of coures vise grips, the second is to weld something on to it like another bold and use it to break it loose. try those and if it dosent work let me know