If you're talking about one week, then you're fine. Doesn't really matter where you put it as long as it is sealed in a bag, but the fridge or freezer would be best. I have brewed with 6 month old grain before (specialty grain at relatively small quantities), and there were no issues with the flavor. Of course, I double bag all of mine to try and maintain some freshness.
One of my best beers that I have made to date (a vanilla porter) was made with 6 month old grain, and it got rave reviews. How long do you think your supplier has had the grains anyway??? Probably not fresh from the oven the day you got it anyway.