Cooking with Port?

[tandkvd]

I picked up a few wines for this weekend. One is an Osborne Ruby Porto. My wife liked it but is way too sweet for me. And my wife could only drink a little. She thought it would be good to cook with in a desert. Any sugestions? Also how long will it keep after opening? I have found that most of the wines that I drink only Keep for about a day. But I thought with the higher sugar content that the Port may Keep longer. And should it be kept in the refrigerator?