Filtering By Date

I have a View with a structure like this

VisitTimes Company
2007-07-10 14:24:38.000 Microsoft
2007-03-10 11:14:38.000 Microsoft
2007-12-01 13:04:56.000 SQLTeam
2007-12-13 12:54:52.000 GoldMan Sac
2007-08-11 02:15:38.000 Oracle
2007-02-11 12:45:04.000 SAP Ltd

I am asked to write a stored procedure that get a count of each count of visit on a START and END date
I wrote the below SP but am not getting the right result
I think the **where VisitTime >= @Start AND VisitTime <= @End)** is not being evaluated. Help pls

CREATE procedure dbo.GetVisits
@Start varchar(50),
@End varchar(50)
as
SELECT TOP 100 PERCENT COUNT(company) AS VisitCount, company
FROM visits.dbo.IViewVisits where EXISTS
(SELECT * FROM VISITS.dbo.IViewVisits where VisitTime >= @Start AND VisitTime <= @End)
GROUP BY company ORDER BY COMPANY ASC