Luke's special, I think it's called "Bullseye" - that one is important for the last battle in Tier6. Very important. It dispels taunt, and they have a double taunt that is terrible to try to fight through, but with Luke's dispel you only have to fight through one and dispel the other - much more doable.
The dispel might also help you in Tier3 as well, since taunts are a problem in Tier3 (though not quite as big a problem). It only has the dispel effect after you give it an Omega. You can get Omegas by battling Stage 8 Cantina Battles. Those are quite hard, but not impossible if your player-level qualifies you for them. If you've only just opened them, you'll need a great ally, but some allies can virtually solo the level.
I really, really don't have the most developed roster around, but if you need an ally that's got toons level 80s, full Omegas, no zetas, gear 10 - I have several toons like that and they are very powerful even if they aren't zeta Savage or zeta Kylo.
But that only helps with getting the Omegas, you'll still have to do Tier3 with no allies.
I think the best thing to do if you have **no hope** of getting an omega on Luke's special (which requires the toon to be level 78) is to give as many ability levels as possible to Han's Taunt to get greater TM increases from each hit. Next, using Han as leader, increase Han's Leadership ability as much as possible. Third, increase the basic attacks as much as possible.
But that all assumes there's no way to get 5 omega mats in the next 2 days. If you can get that many Omegas scraped together, then your best long term plan really is to get Luke's special up to Omega level so you can dispel taunts.