Best at home exercises to build lean muscle?

[justkeeponsmiling]

I am currently doing weight watchers and am on a steady weight loss. I walk a lot so not really looking for cardio-type stuff - I live at the foot of a mountain and go for an hour long up hill power-walk 4-5 days a week which I enjoy. I'm looking for some good exercises to tone my major muscle groups, am doing some yoga at the moment but really looking for something to specifically target arms/abs/gluts/back(fat) to firm up.
I have the Davina fit in 7 mins DVD but if I remember right they do more of a HITTS type exercise which I really don't want - no jumping jacks/burpees etc! I literally just want to build muscle.
I have some good handweights I can use.
Can anyone recommend an app or a good (preferably not too long) youtube routine I could use?

Pilates is really good for muscle tone. It's similar to yoga but it's higher impact and it focuses on one muscle group at a time so if you just wanted abs you can just do abs etc. There's lots on YouTube. Just search Pilates for abs etc and they come up. Also with Pilates you have more flexibility with what equipment you can use. You can do it alone, with an exercise ball, a band, a black etc. I love Pilates and found that I've built a lot more strength a lot quicker than doing yoga alone