1) I know what you mean by the dampened sound. You need to make the chord chnages really smooth and slow down when changing chords. it helps to visualize where your fingers are supposed to be then jsut move them there all at aonce. Its not easy at first but after tons of practice you will wonder jsut what the heck you thought was so difficult.
2) Learning chords or single notes eh? Well i always looked at it from the perpective of what you want to do with your guitar. do you want to play lead or rhythm? If you choose the latter then chords are so important, if you choose the former then learning scales and stuff is important.
Or you could jsut get a guitar teacher who would give you proper direction and focus.