How would I combine these two images without losing information? I have tried the mix node, the alpha over node, and the z combine node, but can't get it to work. Hope someone can give me a helping hand.
First, the word is 'node' :)
Third, the Viewer node is just a shortcut to see what the image looks like after a branch of other nodes have processed a node branch. To build both of these render layers into a finished picture you'll need a Composite node. The Viewer node just gives you the background under the node tree. You can use both: just feed both the Viewer and Composite nodes the same input.