Your current diet + routine = weak ethiopian.
I don't care if you are fat, you need to eat more. Protein in particular. Cheapest probably eggs. And go running. At your age fat should melt off fast and unless your sitting around eating bags of cheetos you shouldn't have to worry about it.
You don't have to buy weights. Find some buckets and fill them with sand. If you don't have sand just use dirt. Find a steel bar or even a stick of wood like a 2x4 and you can have a makeshift bench, squat weight, millitary press weight etc for nothing and will benefit much more over your dumbells. It might sound ridiculous but it will work. And if you really want to get it going......load up a couple 5 gallon buckets with dirt, dog shit, whatever and go walk as far as you can after your workout. That will annilhate your fat little ass and in a few months you'll be thanking me.