About CSV files, Excel, Access, Visual Basic, and exporting and importing data
That does sound easy. The only problem is that I have no idea what a CSV file is.
I think I've thought of a way, but it's a couple of revisions off yet. I just started a week of 24/7 stand-by for work, so it won't be this week.
CSV stands for Comma-Separated Values. CSV files are what we call "flat files" in my field. They can only contain 1 table of data, and so if there are 2 or more tables of data, the tables would have to be "flattened" into 1 table, hence causing repetitions here and there. Not very nice. You have already done a good job with Excel, but if I had been here earlier, I would have suggested using Access, since you probably do not have access to Visual Basic which would have been so much easier to program with for a character sheet of such complexity. In Access, you could have created several tables of data and thus made things a lot easier. This of course requires some knowledge of the basics of database design and normalization, but it's not that difficult to get, considering you managed to do all this in Excel.
Anyway, we're stuck with either Excel or Access along with VBA (Visual Basic for Applications). Access with VBA would have been great and easy to design, export and import. There is also supposed to be a way to integrate Excel and Access, but I haven't tried that before, since I mostly delve in things like C++, Java and Visual Basic. However, I have done Access with VBA before, and it's rather easy to design and implement with. Especially when it comes to your character sheet. Okay, maybe it wouldn't look as close to the pen & paper character sheet, but it would be quite functional and user-friendly if you did the user interface well.
So, unless you can get a copy of Visual Basic and learn how to program with it, you're stuck with CSV files for exporting and importing. So if you have designed your data in a format that wouldn't fit into a single table, you could try exporting the data in separate CSV files (1 table per file), and importing them in the same manner, just in reverse.
Either that, or you'd have to learn Access and VBA and how to integrate it with Excel.
Or, you could get a hold of and master Visual Basic (which will probably take too much time).