The embarrassing loss was followed by the revelations that Lloyds Banking Group had placed a representative on the Rangers board in a bid to recoup some of the club's £30million debt.
Rangers then lost the Scottish Premier League lead to Celtic and Miller admits their hopes of making the last 16 of the Champions League would also slip away if they lose in Steaua's Ghencea Stadium.
So the Scotland striker is desperate to ensure there is no repeat of the first result against Dan Petrescu's men.
"They are far from unbeatable but we need to remember what they did to us in the first game and hopefully turn it around," Miller said.
"It was a very disappointing result. We have got to try to use that hurt to spur us on and hopefully get the right result, so we are coming in after the game in a different frame of mind.
"If we get three points, I definitely think we'll be right back on track."
Rangers fans have been reeling from the realisation of the extent of the club's financial problems and Miller is keen to cheer them up - but he admits the players are also in need of a lift following some below-par displays.
"We want to give ourselves a boost as well," added Miller.
"It hurts us just as much. We are the ones out there who are under-performing at the moment. We want to put it right for us first and foremost.
"Yes, we want to give the fans a boost but we are hurting just as much."
Miller is expected to start and he has proclaimed himself in good shape after visiting a German specialist last month for treatment on an ongoing hamstring problem.
"I feel pretty good, touch wood, and raring to go," the 29-year-old said.
"It's probably the fittest I felt for the last couple of seasons.
"I want to be in the team and up front fighting for goals."
One player who is not fit is Madjid Bougherra, who did not make the trip to Romania this morning as he battles to recover from a knee injury.
And the Algeria defender does not plan to fly out of Glasgow in January despite being one of the financially-troubled club's most valued assets.
"I will definitely stay in Glasgow and finish the season at the club," Bougherra said.
"I love life at Rangers and I'm sure they will find an investor and things will work out.
"I feel great in Glasgow and I need stability because that is one of the keys to success and progress, especially on the eve of the African Nations Cup and a World Cup."
Bougherra, who suffered his injury on the eve of the first match with Unirea two weeks ago, added: "I won't play because a knee injury requires at least four weeks of rest."
Unirea Urziceni v Rangers 1st Goalscorer: Miller, K. 15/2