Hi auntie, and welcome from me as well
The thing to remember is that only part of an app is moved to sd, and that application data use internal storage too. So if you have a large phonebook with many duplicated entries (can happen - it hides the duplicates from you until you try to edit one), or a lot of data cached by facebook or an email app or whatever, all of that is using your internal space.
What I suggest is using the manage applications menu and viewing your apps sorted by size (by data size if your android version gives you that option). See which the big ones are and try clearing caches for them. Also see if there are any which are using many MB of data - if so, is there anything you can do to reduce that? If you have "contacts storage" using 10s of MB you've probably got duplicated contacts in there (I've got > 300 contacts and it uses a couple of MB).
Sometimes uninstalling updates to system apps can help. The system app itself is part of the ROM (so lives in a different part of the storage), but updates use up your app storage space, and sometimes don't clear up old updates properly. In this case uninstalling updates for say Maps, then just installing the latest update, can free up some space.
Good luck, and if you have any questions at all do ask.