Calculate Date Which Is On Every Wednesday

dear all

how to calculate a date which is falls on every wednesday using ms access

for eg

this week enter date : 05/03/2007 and then save

next week automatically display date : 14/03/2007

later next time, enter date : 16/03/2007

next week automatically display date : 21/03/2007


i don't think this is the right formula

=DateAdd("d",7,[run_date])

if i keyin run date : 03/03/2007
it will display using above formula : 10/03/2007
but i want display run date : 07/03/2007 ( falls on wednesday )

what if keyin run date : 05/03/2007
it should be displayed : 07/03/2007 ( falls on wednesday )

any other way the right formula


thanks in advance