List Reconcile Tool - add new functionality

We have an existing reconciliation tool, written in VB.Net that selects customer data (email addresses, etc) from 3 different data sources and compares them with a master database, reporting any errors or discrepancies. The current master database is connected to through a database that is connected to through a WCF interface, for which an API and utility library is in use (.Net). The new stage of the work is to add in a further comparison which will compare email addresses and names selected from mail chimp lists with the master database and then add/modify the master database as appropriate. This is a relatively simple task that is being outsourced due to lack of internal development resource. Good English language skills are essential, as well as good initiative. The work should take no longer than 1 week of programming time. I'm open to either fixed offers or rates.