We all start near the same place you find yourself now, knowing, but not fully accepting or understanding who God is. The relationship with GOd is a life long relationship, and as with any relationship, it grows stronger every day as long as you remain in the relationship, not ignoring Him and what He is showing you about yourself and your relationship with Him. He know you better than you know yourself and is patient with all of us.
Your conscience is a tool within us, used to warn us of wrongs. The question is, by what standards is your conscience working from? What is your measuring stick you use to determine what is right and what is wrong? Those who are His use scripture and learn to listen to the very quiet voice as He nudges us when we are in an area unfamiliar to the standards, or unsure of what to do. You conscience is not the Holy Spirit. The Holy Spirit will convict us of sin through our conscience.
But now I go away to Him who sent Me, and none of you asks Me, ‘Where are You going?’ But because I have said these things to you, sorrow has filled your heart. Nevertheless I tell you the truth. It is to your advantage that I go away; for if I do not go away, the Helper will not come to you; but if I depart, I will send Him to you. And when He has come, He will convict the world of sin, and of righteousness, and of judgment: of sin, because they do not believe in Me; of righteousness, because I go to My Father and you see Me no more; of judgment, because the ruler of this world is judged.
I still have many things to say to you, but you cannot bear them now. However, when He, the Spirit of truth, has come, He will guide you into all truth; for He will not speak on His own authority, but whatever He hears He will speak; and He will tell you things to come. He will glorify Me, for He will take of what is Mine and declare it to you. All things that the Father has are Mine. Therefore I said that He will take of Mine and declare it to you.
You are correct in saying that the Holy Spirit cannot live in the same temple as a demon. Yet, every demon is subject to the authority of GOd, and if it is the desire of the person to be His child, God will clean the temple of any demonic entity and the Holy Spirit will enter. Have you read Luke 11:24-26 and understood what is being said? Notice the verses before, where Jesus is discussing casting our a demon. Now, in the verses below, notice that the house was swept and in order. This is the condition of someone who has been cleaned of a demon, but the house was still empty as the one cleaned did not invite the God to enter in. If the person had done so, then the house would not of been empty for the demons to re-enter. So, if someone who is set free from demons reject His salvation, they will then be worst off then before.
When an unclean spirit goes out of a man, he goes through dry places, seeking rest; and finding none, he says, ‘I will return to my house from which I came.’ And when he comes, he finds it swept and put in order. Then he goes and takes with him seven other spirits more wicked than himself, and they enter and dwell there; and the last state of that man is worse than the first.