Dear Sir,
I can do help you improve in SQL Database.
I'am Dang Quoc Huu, I have 15+ years experience in developing Webform/Winform Applications on C#, VB.NET and SQL Server.
All my products, I have been used SQL Server Database and most business rules have been coded in Store Procedures, Functions, Triggers, User Data Types, ... so I deeply knowedge with SQL.
I know how to increse the query speed. Your problem most in index, if you have good index in tables, the queries speed can many improve.
I beleive that I am a best choice for your requirement.
Thanks and Best Regards.