Welcome to Gaia! ::

If you don't like going outside like me, I have an exercise ball that I use for abdominal exercises. Pilates and yoga is also good to do at home, also maybe a ten pound weight, you can do curls with?
If you sit on the exercise ball with your back straight up and feet planted flat on the floor, and do oh say 10 curls on each arm and if that doesn't feel the burn than 10 more on each arm etc. It works out your arms of course but also your back and legs since you're using those to balance yourself.
Since you want muscle might I recommend an amazing and easy breakfast?

all you need is:
go lean cereal (or just any sugar free granola but Go Lean is yummy)
fat free plain yogurt
blue berries
and protein powder
it's pretty nummy, is great for your digestive system, gives you energy, and helps you stay full without feeling bloated.

there's also a ton of protein shakes you can make with that protein powder, you don't need much, just drink one before and immediately after your workout

my schedule when I can is every other day 2-3 hours of cardio or strength training, with Sunday as a rest or make up day.... if I miss a day or two I have to do it all on Sunday. I haven't been doing to great on it since I've been working so much but at work I'll try to stretch, use stairs instead of elevator.... park on the roof of the parking garage etc.

So maybe
Monday- jogging/running
Tuesday- weights
Wednesday- bike training
Thursday- Pilates or yoga
Friday- stairs
Saturday- mix strength and cardio
Sunday- rest/make up day

just an idea to throw around whee