Setting field value

Hello,

I need my published infopath form to do the following

When a date is selected I need the infopath to look up the date in a SharePoint list a return a vaule.

The list will contain date intervals  (from, to) and each interval will have a period assigned to it

eg

Enter 19/04/2013 in date field

info path query sharepoint list (01/04/2013, 27/04/2013)=Period 1

Period field returns value=Period 1

Please help

Thanks

Roger