You can slightly extend the life of the beans by keeping the bulk in a valve bag or mason jar rather than the hopper, ideally under vacuum. However, this is not anything that can do miracles. A blend where the complexity is in flowers and light fruits is going to be dead as doornail in a week no matter what you do. Deeper spice, chocolate, dark berry, current etc flavors may only get started four or five days out of the roaster.
If you look at the SCAA Flavor Wheel,
http://www.sweetmarias.com/tastewheel2.jpg on the aroma side, the flavors are arranged by molecular weight. The lightest compounds at the top disappear most rapidly, in a matter of days. As you move clockwise and down, the flavors last longer, with the "dry distillates" lasting almost indefinitely. These flavors also correspond to the degree of roast, since darker roasting drives off the lightest compounds first.