Update of an existing MS Word add-in written in VB.NET

We have a decently functioning but bit out-of-date document automation tool, i.e. an add-in for Microsoft Word written in VB.NET which needs to be updated, customized + some new additional desired functionality should be added. We are looking for a clever english speaking programmer with knowledge .of NET framework, VB.NET programming language, Microsoft Visual Studio and preferably also familiar with MS Word object model and Visual Studio Tools for Office. The project is not urgent and has no deadlines, however we want to start soon and get at least 20 hours of work per months to be done.