Financial Data Analysis with Pivot Tables Open

We have a point of sale system that does not provide the type of reporting that we need, therefore, we download POS data into an Excel spreadsheet. Our spreadsheet has a number of complex formulas that may, or may not, be the most efficient way to get the data. What we need is for an Excel expert to review the spreadsheet's structure and suggest/make improvements. Then we need pivot tables built to analyze the data.