I've felt this way before and am often looking for more ways to do for God. It's nice to see someone who wants to do more for God. Maybe it's me, but I feel like the fact that you even want to do more for God means you're probably not lukewarm. Lukewarmth, to me, at least implies some level of apathy.
I'm at home a lot. If you want suggestions of things to do for God while staying at home, I have a few I can PM you if you would like.
Meanwhile, whatever you do, do it with your whole heart. As someone said earlier, God looks at the heart.
Quality over quantity.
That does more than you even know.