How can I get a direct stream of water out of my kitchen sprayer hose?
Sprayers don't last forever. You can try replacing the sprayer and hose to see if that solves the problem. There could be some bad washers which are making a poor seal. This could be why you aren't getting a good flow from the sprayer.

Since you stated that the current faucet you have is a basic model, you could also invest in a replacement one. These can usually be replaced without needing very many tools. You would want to have some basic plumbing tools such as water pump pliers and an adjustable wrench. These tools will vary depending on the style of faucet you have, so you should consult with an employee at the store to see what they would recommend.

You can also try filling the humidifier in the bathtub if you have one. This is what I typically do. There is much more room underneath the spout and it fills up pretty quickly.