Maybe try to post the stored procedure. I'm pretty good with these.
From what your saying about multiple selects ect.. Sounds like that's likely the problem. Check that you have adequate indexes on the tables used in the stored procedure. Use explain plan on the SQL statements to see what's happening.
As Mark said there is a loads of stuff you can do on the oracle for performance,
but usually it's the application code that's the problem i.e. your stored dprocedure.