What AF Area mode should i use

I have a Nikon D3100. I started out using the auto af area mode at first. Then, i found out that its better to use single point or dynamic. I gave it a try and i've been using single point for awhile now. But now i'm reconsidering. Since the camera only has 11 auto-focus points, does it matter? Also, the button pad is pretty uncomfortable. I like taking portraits with my 50mm 1.8 but since the camera has only 11 auto focus points, when i focus on the eyes, every picture looks exactly the same, dead center to the right or left. Should i stop using single point and go back to auto? Or should i should i upgrade to something like the D7000? I would love to upgrade but i'm broke and my parents won't ever let me sell anything that i have to get money. Any tips or advice will be greatly appreciated.

Single and Dynamic both have their uses. Dynamic for when you have little or no time, single if you want to be precise.

I suggest you revert back to your manual and read about the AE-L/AF-L button on your camera, that may be just what you need in this stage.

Learn the advantages of all the different AF modes, they all have their uses - that's why they are there.

You could also try using the manual focus mode too, if you are taking portrait photos manual focus is the way to go in the long run. Sure it takes a little more time, and it's possible to get it wrong, but when you do get it right the results can be fantastic.

So you have no idea how to focus, lock, recompose, shoot? It is how photographers have used auto focus for ages. You put the auto focus point where you want on the subject, hold the shutter button half way down to achieve focus, and WHILE HOLDING THE BUTTON HALF Way DOWN, you recompose the shot as you want. Focus will remain locked. You then take the photo. The focus and the composition will then be as you want them.

I always use the center AF point, and the AE/AF lock to re-compose.