Database Design - MS Access

I need a database to run a few queries and create a report based on two tables. I would like to automate the production with macros that run off menus. There would be one main menu that opens when the file opens, with buttons asking to Import Data, Export Data, Run Reports. I would like to compare the file from one year to the file from another year. I am working with some very large payroll files, thus I am somewhat concerned about size. I do have a SQL server that I can use but I need the controls to run through Access. I would want to be able to use copies of the access file to run/export payroll for separate states and compare separate years. I have prepared prior years data manually, but I am hoping to automate certain processes. The data comes to me in multiple text files (between 1 and 4 files, each up to 800MB) that are separated by a degree (°) symbol. I need to combine all of these test files into one file, add a few columns bases on formulas, and summarize the data into a new table. I want to compare the summarized table to the prior year's summary the reports. The queries are relatively simple - one to add a few columns to the base table based off formulas, and another to summarize the base table. The reports I am looking for are also relatively simple - one would compare totals from the file from one year to total from the file from the other year. The other would compare certain columns of matching records from each year. I would appreciate any ideas experienced designers have concerning the design of this program.