How can I use a Query String Field in my DataReader ?

I am trying to include a "Where" filter in my DataReader with the filter being provided by a Query String Field (or similar)
My DataReader is currently as follows, and I want the "@Agreement_ID" to be provided by a Query String Field.
        Dim reqdfrom As DateTime         Dim reqdto As DateTime         Dim newfrom As DateTime         Dim newto As DateTime         Dim sConnection As String = ConfigurationManager.ConnectionStrings("locumdatabase1connectionstring").ConnectionString         Using Con As New SqlConnection(sConnection)             Con.Open()             Using Co ...