If you want to tone your upper body at home, try 3 types of pushups. Those are; normal, wide armed, and diamond (when your thumbs are touching near the middle of your chest). For abs, find a nice balance between traditional sit ups, crunches, and leg lifts. Get a dumbell or two, and do curls with your arms, some military style pressing, and reverse curls behind your head (careful, I've seen people drop weights on their neck). for your fore arms, get a pice of pvc pipe, about 2 feet long at around 3" diameter, drill a hole in the middle and tie a short rope 3 feet into the hole. Then tie a weight (it will be a light weight) to the other end of the rope and roll the rope onto the pvc using your hands while bending at the elbows, then change directions of rolling. You also cant beat a pull up bar, or a sturdy rafter.
This will make you strong, but it will not necessarily give you maximum bulk, most will be lean muscle obtained by many reps. If you wish to bulk up, you will probably need to go to a gym, and use maximum resistance with minimal reps.
Oh yes, as far a quantity of all of these, its pretty much until you can do no more. Then take a day off the muscle group you just maxed. so.. Situps, cardio, forarms one day perhaps, then pushups, curls, bicep, cardio the other.