Everyone starts somewhere, so there are no dumb questions here.
If the TV is a 1080p TV, then it has a 1080p panel. Meaning that regardless of the signal coming in, the picture is processed (and if necessary, upconverted) to 1080p resolution. So basically, whatever picture you put into the TV, it will show it at 1080p. The closer it is to 1080p, the better the picture quality will typically be.
What you're seeing with the INFO bar (where it lists resolution and Hz) is the resolution and Hz rating of the INCOMING signal. In most cases, broadcast HD signals are 720p and 1080i - not very many signals are actually broadcast in 1080p for bandwidth reasons. (It's very expensive for the broadcasters). So, as the 720p and 1080i signals are HD signals, but that's how they are coming in.
If you have a Blu-Ray player, or game console, or attached box, there are some cases where you can increase the resolution from the source, but that has to be done in the menu of the game console or the cable/sat box. When you have a game console or a Blu-Ray player, this is a good indication of what your source settings are.
Does that help?
If you have any further questions, please let me know.
First off I'd like to apologize if this is a dumb question but my HD cable box does not have any type of buttons that will let me change resolution or anything like that. Also my HDTV keeps saying the source is in 720p when I know for sure that some of the channels I view are in 1080p. The model is LN46B550.