No, Oracle Database Gateway (either the "free" ODBC one or the licensed SQL Server one) are tools to connect to ODBC / SQL Server data sources FROM an Oracle database, and not in the opposite way.
You may have better opinions researching on a MS SQL Server forum, but the basic steps are described here:
If you are starting from MSSQL, and from there access data from Oracle, then you need to set up a 'shared server' in the MSSQL database. Since you are talking about configuring the MSSQL, you'd be better off asking in the appropriate MS forum.
Now, if you were in an Oracle database and wanted to access data from MS, then we could help you setting up a 'database link' and configuring the 'oracle transparent gateway'.