Gain muscle. I'm OK in the fat department. I just don't have the discipline right now, except for running, which is already a habit for me. That just keeps me at a status quo, though.
All I know about gaining muscle is fewer reps, more intensity. And lots of protein, maybe. And that you are either gaining muscle and fat, or cutting fat without gaining muscle, hard to do both. Haven't read every post in this thread in detail yet, but plan to.
I'm in night class right now, but when I get some time, I will put the equation on here to calculate your calorie maintenance requirement. For instance, my maintenance requirement is around 2900 calories per day. Hence, if I eat a balanced diet of 2900 calories each day, I should stay the same weight. Since I am cutting fat at the moment, I am trying to cut 10-20% of my calories each day. For you, you will want to consume an EXTRA 10-20%.
Also, since you are trying to gain muscle, try to consume around 1.5 grams of protein per pound of body weight each day, but no less than 1g/lb/day. You need protein to build muscle.
As far as your workouts, you can ask Chaddyboxer what he thinks as well, but here is what I would do: HIGH reps, MEDIUM weight. This is what will give you the most burn on the muscles that you are trying to work. Weight lifting is all about muscle concentration and muscle confusion.
-muscle concentration - use correct form and work as hard as you can to flex the muscles for the lift that you are doing.
*example - when doing situps, squeeze your abs as much as you can.
-muscle confusion - comes into play a couple of months down the road when your muscles have gotten used to your "routine". When this happens and you are no longer sore the next day, find new lifts to do that break away from what you normally do.
There's a start. Hope it helps.