Cs-Cart Offline Credit Card Plugin Modification

Hello, I am using Cs-Cart Professional v.4.1.5 for my online store. I use offline credit card payment module for my customers. Normally customer enters his/her credit card information then creates order, then we process the total from our mail order POS system. Default Cs-Cart offline credit card module comes with only one validation. It checks whether if a credit card is Visa, MC or etc. However i need more validation before customer creates an order. There are: 1- Is the credit card number correct ( or valid ) 2- Is expire date is correct ( valid format and not expired dates ) Offline process module uses [login to view URL] file and it use 2 different javascript to work. Al i need is to modify these files so the module also check all credit card validation steps. Budget for this job is $50. Please do not bid more. Expected working time is 3 days. Milestone will be released after module tested. Have a good day.