I've had a bit of personal experience with Ritalin. I focus very well on things which interest me, but I have a much harder time focusing on anything less interesting. I tried Ritalin very briefly (for a few weeks). As far as I could tell, it just made everything equally "interesting", and I could focus on whatever I chose to.

Definitely consult with a doctor, preferably one who specializes in this type of medication. Keep in mind that everything has a side-effect, and that mixing various drugs (illegal or not) can have unexpected results. In other words, learn as much as you can about anything you might use, and decide whether to use it based on that.

I'm also about whether AD(H)D is a real condition in the sense that some people have it, and others don't. However, I definitely agree with the sentiment in one of the other replies below, of how it's like vision -- everybody has a different preciseness of vision. If your vision is bad enough, you get glasses. If you believe that your attention problems are bad enough (they seem to be, from your post), then consult with a doctor.

I hope you find a good treatment.