2004 Colorado rear differential HELP

So I went to change out my rear differential oil and the fill plug is in so tight that it stripped the plug. I was wondering if anyone thinks its a good idea to drill out the plug and retap it with a slightly bigger size plug or if someone could find a cover with a fill bolt for relatively cheap ( I don't want any of the over $200 performance ones ). If anyone has any other ideas that isn't drilling it out with a new plug or the new cover I would love to hear them. I am telling you that bolt would not come out even with an easy out, heat, a breaker bar, and a lot of penetrating fluid. I am trying to not break the bank. The differential cover would need to fit the gm 10 bolt 8.0" ring gear differential. It is from my 2004 Colorado z71 4x4 package