Date problem in Selection formula

Hi,
I am using Crystal Reports 9 and i am facing some problem in creating a selection formula to select some records in between a range of given dates.

MY DATE PARAMETER IS A STRING AND I NEED TO CONVERT IT TO DATE TYPE

Actually I don't know how to make to needed selection formula. What i really needed is to select record sets in between a range of dates which is given as parameters to the reports

Pls help
JOBINuse record selection formula

urfield >=dateparameter1 and urfield<=dateparameter2