Is there such thing as a spreadsheet object/library

Answer 1

Microsoft Excel?

You don't have spreadsheets, you have described flat files with mixed formats and some metadata. What in your flat files says that the sales data is in A6:E22? In fact what does A6:E22 mean outside the context of Microsoft Excel and in the context of your data?

There are lots of ways for you to handle this data from parsing it yourself long-hand and supplying code to manage the data formats to loading it into a set of database tables and using SQL to break it into pieces. Which you choose depends on what the data is, where it comes from and what you are going to do with it. If you provide a bit more of that sort of information a choice of approach may be easier to recommend.