Access db data upload from excell file

I have a access db and i have excell spreadsheets which match fields in the access db. i would like someone to write a upload script on my access db so i can do the following: 1. update the access db data buy uploading excell spreadsheet content - if data exists it updates with new data from the spreadsheet or if the field is blank in the spreadhseet it doesnt update on access db 2. add new data that isnt in the database using excell spreadsheet. i have the spreadsheet and the db ready. consists of about 30 fields that need to be updated. but file may contain upto 100 records. this is a small job anbd should only take someone that is good at access about 2-3 hours