You are quite right about drunkards not being allowed into heaven, as is seen in the passage below:

1 Corinthians 6: 9 Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived. Neither fornicators, nor idolaters, nor adulterers, nor homosexuals, nor sodomites, 10: nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners will inherit the kingdom of God. 11: And such were some of you. But you were washed, but you were sanctified, but you were justified in the name of the Lord Jesus and by the Spirit of our God.

There are people that say that they are addicted, trapped and can never escape their addiction, and that God will have to forgive them in their sin. But that is saying that Satan is stronger than God. God saves us from our sins, not in them, and He says that we should be transformed, born again, changed.

Rom 12: 2 And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is thatgood and acceptable and perfect will of God.

It is very difficult beating any addiction, as you are experiencing. What you need is a strong support group who will make your case a matter of continuous prayer. If you do not have such a support group, you will have to join up with a 12-step programme, such as Alcoholics Anonymous. These programmes all acknowledge our weakness in such matters, and rely on God’s power to change us, and to keep us from the addictive substance.

One thing is certain, very few people have the strength and will power in them to kick an addiction. Start every day by saying to God: “Lord, I have no good thing in me, so I hand over to you my mind, my life, my time, my money, everything. Live in me today, and work in me to transform me. Lead me every step of the way through the temptations that lie ahead, and change me this day more and more into your image”. And He does! It may take some time, and you may fall, but turn it over to Him again, and He will do what is necessary. Nobody need be an addict to anything, for God is able to do everything that is needed to transform us! Remember, God loves you and wants you to be successful in beating your addiction, and He is able to make that change. But God never forces the issue; you must want to change, continually stay in touch with Him and hand over your life to Him. Never, never stop praying and believing that God will do what is necessary in you. God bless as you walk through this difficult time with Him!

Philippians 2: 13 for it is God who works in you both to will and to do for His good pleasure.