If my camera is shooting in 10.0 or 12.0...what will my megapixels be? I am a beginner and I know I need them to be at least 1600x1200 for my purpose.
1600x1200 requires only 2 megapixels, as @coneslayer mentioned in his comment.
Anything above that in number of megapixels will be enough. Most cameras call that resolution, image size or simply megapixels.
There is also often a quality setting which does not affect the number of megapixels but the image compression. This basically works by removing details from those megapixels to make the image smaller in terms of storage.
If your settings went down to 2 MP, which is what you need then I suggest you use the highest quality setting. If your camera gives you, the choice of 12, 10 or 8 (let's say), then it does not really matter for your purpose.
Remember that once you reduce resolution or quality in-camera, there is no way to get any back. So, unless storage is tight, shoot at the highest resolution and quality and then use software to size the image as needed. All image software can do that and many can do it in batch on export or publication. For example, Google Picasa lets you choose the size at which to send images to Picasaweb.