The Bible does say that all Leaders are put in place by God for His purposes. There are many examples in the Bible of Bad leaders - we need to remember that God is Sovereign and above all. Not one bad leader is more powerful than God.
Like Tator said, we need to respect and pray for Obama because he is our leader and like it or not was put in place by God for this appointed time. Personally I have a hard time with this. His policies are killing America and go against everything I hope and dream for America. Still we are supposed to love him - one of my biggest struggles right now. Your pastor is dead wrong in saying we need to do everything he Obama says. Show me that in the Bible. Christians must rememeber that above all God is supreme. We must answer to Him first. The book of Daniel comes to mind since I have just read it this week. Shadrach, Meshach, and Adenego (spelling is way off) refused to worship the statue of the king. They were thrown into a firery furnace for there refusal. They were miraculously protected by God but they were not guarenteed this. They said God is our number one, He will protect us if he chooses and if he dosen't so be it, we will not worship the king. The same thing happend years later to Daniel. In an effort to trap Daniel some politicians had a decree made that anyone that prays to any god other than the king would be throen into the lions den. Daniel prayed opening to God and faced the consequences. Again God protected him. In both instances, God was glorified and the true followers of God elevated in the worlds eyesbecause of there faithfulness.
One other point - I just finished reading a book by Craig Groeshell (spelling again) called "Christian Atheist - Believing in God but living as if He dosen't exist" He has a chapter that talks about if the church isn't what you want it to be, dont quit going but work harder to make it what it should be.