Have you just tried putting the parameters into the query that you already have?
ALTER procedure [dbo].[sp_email]
(
@dept varchar (50),
@exp varchar (50)
)
as
DECLARE @tableHTML NVARCHAR(MAX) ;
SET @tableHTML =
N'<H1>GSR Time Entry</H1>' +
N'<table border="1">' +
N'<tr><th>Employee ID</th><th>Employee Name</th>' +
N'<th>Age</th>' +
CAST ( ( SELECT td = E.Employeeid, '',
td = E.Name, '',
td = E.Age, ''
FROM Employee as E
WHERE DepartmentName = @dept AND Experience = @exp
FOR XML PATH('tr'), TYPE
) AS NVARCHAR(MAX) ) +
N'</table>' ;
EXEC msdb.dbo.sp_send_dbmail @recipients='trial@yahoo.com',
@profile_name = 'seema',
@subject = 'Time Sheet',
@body = @tableHTML,
@body_format = 'HTML'