Customise osCommerce CSV weight based shipping module

Hi, I need someone to modify a shipping module for osCommerce 2.3 for a CSV file, weight based shipping module. I have a module to do most of the job, but need modifications to include different pricing for total cart weight levels for each postcode (zipcode) range entry in the CSV file. The file would look like: postcode from,postcode to, weight1, price, weight2, price, weight3, price, weight4, price, weight5, price e.g. 0000,1234, 0.5kg, $3, 1.0kg, $5, 3.0kg, $7, 5.0kg, $11, 25.0kg, $40, 999.9kg, $80 1235,2345, 0.5kg, $5, 1.0kg, $7, 3.0kg, $9, 5.0kg, $12, 25.0kg, $50, 999.9kg, $100 .....etc Thanks,