From your weight I'm guessing you're already quite skinny? (and can see your ribs a bit)
This means that you don't need to worry too much about losing weight, and it's really more about adding some muscle.
I'd do a 3 day cycle - day 1 for your chest and triceps, day 2 for your back and biceps, with day 3 for your legs. Also work your abs every day, and you should get some good results - this is what I've been doing, and have added quite a bit of mass, and some definition as well - I was a bit chubby 2 months ago, now I can see my abs if I tense (still not too well defined, but definitely visible)
DAY 1:
Barbell Bench Press 3 x 12. Ideally you want to be able to complete the first set, but be going to failure on the next two.
Dumbbell Incline Press 3x12. Same as above.
Skullcrusher 3x12. Make sure to keep your elbows really close together so you can widen if needed if you fail.
DAY 2:
Low row 3x12
Deadlift 5x5
Barbell curl 3x12
Hammer curl 3x12
DAY 3
Squat 5x5
Leg Extensions 3x12
NOTE: Bench press / incline press / squats / deadlifts / curls will all train core a lot as well. In addition I'd throw in 3x40 crunches and 3x40 Russian twists at the end.
Good luck
