[Koha] Data Migration

Dear Members, I am very much interested for using Koha at our organization. At present we have our in-house developed software which was developed with visual basic and back end as Microsoft access. I have installed Koha at our end. It is providing good feature and fulfilling our organization library requirement. can you provide the procedure to import my existing database from microsoft access environment to koha environment so that we can switch over in Koha??? with regards hemu agrawal