working out lead times with 2 dates

Hi

Please can someone help me to work out lead times on my sheet.

for example: if the order date = 07/06/12 and due date = 14/06/12 then the cell with lead time should state 2 weeks.

In addition can it still show a result if the value is not an exact week i.e. 1½ weeks or 1week & 2 days (ideally)

ive attached a sheet to show what im after.

thanks