Direct SQL Execution To Get Count Using Enterprise Library

I am new to asp.net development and using enterprise library in my application in the following way.

Database db = DatabaseFactory.CreateDatabase();
DbCommand cmd = db.GetStoredProcCommand("sp_MakePayment");
db.AddInParameter(cmd, "@BillGenID", System.Data.DbType.Int32);
db.SetParameterValue(cmd, "@BillGenID", billgenID);
db.AddInParameter(cmd, "@PayDate", System.Data.DbType.String, 50);
db.SetParameterValue(cmd, "@PayDate", mypaydate.Text);
db.AddInParameter(cmd, "@TransNo", System.Data.DbType.String, 50);
db.SetParameterValue(cmd, "@TransNo", transno.Text);
db.AddInParameter(cmd, "@AmtToPay", System.Data.DbType.Double);
db.SetParameterValue(cmd, "@AmtToPay", Convert.ToDouble(paidamount.Text));
////Execute Stored Procedure
int i = 0;
i = db.ExecuteNonQuery(cmd);

Now I am in a situation where i need to run this inlnie query using the same method to get the count of records and read in a variable. for example following query to find existing bill.

string bill_id = "1234";
string dofpayment = "11/03/2011";
mysql = "Select count(*) from payments where bill_id = " + bill_id + " and payment_date = " + dofpayment ;

Now how to incorporate the above lines using the enterprise library block.