At a minimum, I think we have to beat UNC, Miami, and Wake to crack the top 25. However, even if we do that, it's possible that we could still be unranked when we play Clemson.
Assuming we win through Wake, our wins will have been against an FCS team, 2 teams with losing records (Pitt and UNC), a historically bad team (Wake), and a question mark in Miami (I know they beat Toledo by 22, but they struggled early and only had a 1 score lead going into the 4th). Add that to the normal anti-ACC, anti-Option/GT bias, we won't be given credit for having any quality wins.
If Miami crushes Duke and FSU and we beat them, then we'd get some credit, but, unless that happens, it may take a Clemson win to get us into the top 25.