Academic Amnesty-vs-Transferring: how does each affect graduate school admission?
Whatever you do, it's worth keeping in mind that those reading through grad school applications are people as well. They understand that whatever happened 20 years ago will not be who you are today. So, if you have good grades in your most recent courses, and if you have good GRE scores, then they will be quite likely to disregard your grades from the last century. Just point out in your application essay that you have had a few hard years back in the day but that, as can be seen from your most recent transcripts, you have changed and gotten yourself back on track. Honesty pays in this regard, and whatever your GPA will be does, in that case, not matter all that much any more.