First off, you should try to Upvote a little bit less. There is Steem Power (how powerful your account is, and thus your maximum potential Upvote) and then there is Voting Power which recharges daily. Go to @PenguinPablo's website www.steemnow.com , and type your username in and hit Save. This will show you your votoing power, which for you, is really, really, low right now. So you can keep posting and commenting but try to not Upvote for at least a couple of days so your Voting Power can recharge some.

Also, to answer your question about the payouts. If your comment or your post gets upvoted, and you see a $ reward amount, you can check your wallet exactly 7 days after the post or comment and you will see a green box in your wallet (in your profile) that says Redeem Rewards to Balance. Click the button and the rewards will go to your wallet! As far as buying Steem Power, I'd recommend doing that while the price of Steem is fairly low (preferably under a dollar). You can do this by going into your wallet, clicking on Steem Power, and then clicking Buy, which will take you to a screen where you select which currency you want to buy it with. THey accept many. Then, once you've done that, and typed your Steemit Username in the box (johnbcheffin12), they will give you a unique Address to send to. Hope this helps!