how do i perform all insert,update,delete and select using single stored procedure

CREATE PROCEDURE [dbo].[prc_UserAddUpdate]
(
	@MCUSXintIde0 as int=0, 
	@MCMPXintIde0 as int=0, 
	@MCUSXvarFnm0 as varchar(100)='', 
	@MCUSXvarLnm0 as varchar(100)='', 	
    @Action as varchar(100)='',
	@strId varchar(500)='',
	@ReturnVal int out
)
As

---------------------- ADD SECTION START ------------------------------------
If @Action='Add'
Begin
	If exists(select 1 from tbl_MCUS where MCUSXintIde0=@MCUSXintIde0)
	Begin
		set @ReturnVal=0            -- Unsuccessful Addition
	End
	Else
	Begin
		Insert Into tbl_MCUS
		(
			MCMPXintIde0,MCUSXvarFnm0,MCUSXvarLnm0
		) 
		values 
		(
			@MCMPXintIde0,@MCUSXvarFnm0,@MCUSXvarLnm0
		)
		
		set @MCUSXintIde0 = @@IDENTITY		
		set @ReturnVal=@MCUSXintIde0   -- Successful Addition
	End
End
---------------------- ADD SECTION END ---------------------------------------
---------------------- EDIT SECTION START ------------------------------------
Else If @Action='Edit'
Begin
	
		update tbl_MCUS set
			MCMPXintIde0 =@MCMPXintIde0 ,
			MCUSXvarFnm0 =@MCUSXvarFnm0 ,
			MCUSXvarLnm0 =@MCUSXvarLnm0 			
		where MCUSXintIde0=@MCUSXintIde0		
		
		set @ReturnVal=@MCUSXintIde0	 -- Successful Edition
	
End

---------------------- EDIT SECTION END --------------------------------------
---------------------- DELETE SECTION START ----------------------------------
Else If @Action='Delete'
Begin
	delete from tbl_MCUS where MCUSXintIde0 in (select Items from Fun_SplitInt(@strId,'#'))
	set @ReturnVal=1	 --  Successful Delete
End
---------------------- DELETE SECTION END ------------------------------------

ALTER PROCEDURE spBooks
@CommandName VARCHAR(10),
@CommandValues VARCHAR(MAX)
AS
BEGIN
	DECLARE @Data VARCHAR(MAX), @BookID INT, @Title VARCHAR(100), 
	@PublisherName VARCHAR(30), @PublishedDate DATETIME,
	@pos1 INT, @pos2 INT, @pos3 INT, @pos4 INT
	IF(@CommandName='SELECT')
	BEGIN
		SELECT * FROM tblBook
	END
	ELSE IF(@CommandName='UPDATE')
	BEGIN
		--Splitting all the data and storing in the variables
		SET @Data=@CommandValues
		SET @pos1=charindex('±', @DATA)
		SET @BookID=SUBSTRING(@data, 1, @pos1-1)
		SET @pos2=CHARINDEX('±', @DATA, @pos1+1)
		SET @Title=SUBSTRING(@DATA, @pos1+1, @pos2-@pos1-1)
		SET @pos3=CHARINDEX('±', @DATA, @pos2+1)
		SET @PublisherName=SUBSTRING(@DATA, @pos2+1, @pos3-@pos2-1)
		SET @pos4=CHARINDEX('±', @DATA, @pos3+1)
		SET @PublishedDate=SUBSTRING(@DATA, @pos3+1, @pos4-@pos3-1)
		
		--Updating the records based upon the BookID
		UPDATE tblBook SET Title=@Title, PublisherName=@PublisherName,
			PublishedDate=@PublishedDate WHERE BookID=@BookID
	END
	ELSE IF(@CommandName='INSERT')
	BEGIN
		--Splitting all the data and storing in the variables
		SET @Data=@CommandValues
		SET @pos1=charindex('±', @DATA)
		SET @Title=SUBSTRING(@data, 1, @pos1-1)
		SET @pos2=CHARINDEX('±', @DATA, @pos1+1)
		SET @PublisherName=SUBSTRING(@DATA, @pos1+1, @pos2-@pos1-1)
		SET @pos3=CHARINDEX('±', @DATA, @pos2+1)
		SET @PublishedDate=SUBSTRING(@DATA, @pos2+1, @pos3-@pos2-1)
		
		--Updating the records based upon the BookID
		INSERT INTO tblBook VALUES(@Title, @PublisherName, @PublishedDate)
	END
	ELSE IF(@CommandName='DELETE')
	BEGIN
		DELETE FROM tblBook WHERE BookID=@CommandValues
	END
END

USE [RupaDB]
GO
/****** Object:  StoredProcedure [dbo].[P_SP_Action]    Script Date: 01/01/2014 02:10:37 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER procedure [dbo].[P_SP_Action]( 
	@Action varchar(20),
	@EmployeeNo varchar(20),
	@EmployeeName varchar(20),
	@DateofBirth varchar(20),
	@Gender varchar(2),
	@Age varchar(20),
	@Designation varchar(20),
	@MobileNo varchar(20),
	@State varchar(20))
as
begin
	declare @EmpId int;
	begin transaction
		set @EmpId= @@IDENTITY;
		if(@Action=1)
		begin
		--For Insert
			insert into mst_Employee(EmployeeNo,EmployeeName,DateofBirth,Gender,Age) values(@EmployeeNo,@EmployeeName,@DateofBirth,@Gender,@Age)
			insert into mst_Employee_Official(EmpId,Designation,MobileNo,State) values(@EmpId,@Designation,@MobileNo,@State)
		end
  
		--For Update
		if(@Action=2)
		begin
			update mst_Employee set EmployeeNo=@EmployeeNo,EmployeeName=@EmployeeName,@DateofBirth=@DateofBirth,Gender=@Gender,Age=@Age
			update mst_Employee_Official set EmpId=@EmpId,Designation=@Designation,MobileNo=@MobileNo,State=@State
		end
 
		--For Delete
		if(@Action=3)
		begin
			delete mst_Employee 
			delete mst_Employee_Official
		end
 
		--for Select
		if(@Action=4)
		begin
			select * from mst_Employee
			select * from mst_Employee_Official
		end
 
		if(@@ERROR=0)
			commit
		else
			rollback
		end