Oracle offers a Data Migration utility that can help you move data from SQL Server to oracle. I think that is a seprately-licensed product that you need to buy and install separate from the Oracle database software. If you get that and use that, it should get all of the data transferred to Oracle. But, that is only part of the problem you face though.
A bigger problem may be how to convert SQL Server stored procedures to Oracle stored procedures that work efficiently. As far as I know, there is no automated tool to help with that. And, the stored procedure languages are very different between these two database systems. Usually, some manual coding changes are necessary to handle things like: date comparisons; null values; whether temp tables are used or needed (in Oracle usually not); returning of record sets from procedures (this is not the default in Oracle), etc.
