Okay, math wasn't my major in college but I think I've got this figured out...
After the PM Games on 9/22/12 (after Game 131), this is what I've figured so far:
(1) The Top 16 teams in each league automatically earn a berth in Round TWO. If the season were to end right now, in most of the leagues, you would have to have somewhere between 59 and 64 wins to get one of those spots. For example, in League 6, the sixteenth best team right now has 64 wins, while in League 7, the sixteenth best team only has 59 wins. The current list is as follows (I'll list the 16th and the 17th best win total for each):
(2) After the first 160 spots are figured out, the final 32 spots will go to the teams with the best W/L record (across all 10 leagues) that aren't included in the above. Currently, that will take it down to the 60-win mark. In other words, should the season end today, if your team has 60 or more wins right now, they'd be in Round TWO. The only exceptions would be the two 59-win teams in League 6 and League 9 that would grab the sixteenth spot in each league.
(3) Dividing 60 by 131, this tells me that the current winning percentage a team must have to make it to the next round is (rounding off) right at .458. Projecting a .458 winning percentage for a 162-game season, you should need to have at least 74 wins to have a shot at moving on.
Let me know if you see any miscalculations in my figuring - I think I did it right though. Please don't take these figures as the gospel though. It's not a perfect formula by any means but it tells you approximately what you need to shoot for.