Take Her to the game and buy Her anything at Fed Ex she wants. Tell Her that "There is no where in the world I would rather be.Then with you celebrating one of the best days in world history(a.ka. Her B-Day)with you and our Washington Redskins!"
Try not to get too wasted and take her to a nice dinner after words. That's what I would do.
If She doesn't go for that just take the B-tch shopping on Sat!Then you will be free to ditch Her ass during the game on Sun.
p.s That last part was a joke.

I am sure she is really really sweet.