[Koha] Help needed

Hello , I am facing some problem in importing my database to KOHA 3.12. In fact in my office we are using some library information system application (troodon) which i can only work in it but i cannot do anything with the database. It has been restricted by the vendor. They are using the MS-SQL 2008 as the database. But we can take a backup of this database (thru this apps) and it get stored as *Troodon5201408181600.bak* *I have installed KOHA 3.12 but i can't import any of my data from my old software * Please suggest what/how should i do to import this database to KOHA. Thank you in advance. dominic shillong(meghalaya) india.