I recommend using the MSOffice Interop classes to open and read the Excel document and dump it into an XML format. Once this is done you can bring it into a DataTable which can then be brought into the BO.
we had the same type of problem (Excel to Oracle) and in the end decided to use a commercial tool/component from Syncfusion (http://www.syncfusion.com/products/xlsio/windows/default.aspx) together with SF in a VB.Net environment. That solution worked fine for us.
Kari