[Koha] import data to koha

Dear all, writing from an educational institution in india. we already have a library management package, which was made locally. we have installed koha and is planning to migrate to koha. can you please help us find out how we can transfer the data from the existing database to koha? the help required is to transfer the data of books into the koha database. we dont have marc records, but has isbn number, title, prince and all such details of all the books in the existing database. I have someone helping me with mysql also. thanks -- unnikartha