For populating the data from dataset to a Word document you have many options as below.
Use Microsoft Word Object Library COM component to write a word document or populate a template (.dot) you can refer
http://support.microsoft.com/kb/316384 KB article.
Though I am using Option 3 (ASPOSE) for many years , from your requirement I would recommend you to use Option Two if you have Office 2007 else Option One.