Help me with my golf game.?

I'm a pretty athleteic guy. Played baseball and football all my life and hit clean-up for my varsity baseball team for 2 years. I am 21 years old and have been playing for about 3 months (Beg. of Feb '07). I am left-handed and my biggest problem is I hit everything to the left. I have read Harvey Penick's book and watched a couple DVD's. I have scratch golfer buddies and they told me I have an outside-in swing that's why I slice. Also I drive only about 240, which I should be hitting longer. Also, have taken one lesson. I am just basically here asking for any help or advice that you would be able to tell me. It feels like at times I take 2 or 3 step forwards than a couple days later I take 2 or 3 steps back. My best score is a 101 (all scores I keep are legit make all putts and no mulligans). My goal is to shoot consistantly in the 80's by the end of the year. I believe that is attainable, just let me know any help you could think of for me to help reach that goal. Thanks